Genetic diversity and relationships of diploid and tetraploid cottons revealed using AFLP

Gossypium species (± 49) represent a vast resource of genetic diversity for the improvement of cultivated cotton. To determine intra- and inter-specific genetic relationships within a diverse collection of Gossypium taxa, we employed 16 AFLP primer combinations on three diploid species, Gossypium herbaceum L. (A1), Gossypium arboreum L. (A2) and Gossypium raimondii Ulbrich (D5), and 26 AD allotetraploid accessions (Gossypium barbadense L. and Gossypium hirsutum L.). A total of 1180 major AFLP bands were observed; 368 of these (31%) were polymorphic. Genetic similarities among all taxa ranged from 0.21 (between the diploid species G. arboreum and G. raimondii) up to 0.89 (within G. barbadense). Phenetic trees based on genetic similarities (UPGMA, N-J) were consistent with known taxonomic relationships. In some cases, well-supported phylogenetic relationships, as well as evidence of genetic reticulation, could also be inferred. UPGMA trees and principal coordinate analysis based on genetic similarity matrices were used to identify genetically distinct cultivars that are potentially important sources of germplasm for cotton improvement, particularly of fiber quality traits. We show that AFLP is useful for estimating genetic relationships across a wide range of taxonomic levels, and for analyzing the evolutionary and historical development of cotton cultivars at the genomic level. Received: 17 January 2000 / Accepted: 4 May 2000     

<Emphasis Type="Italic">SnRK2</Emphasis> Homologs in <Emphasis Type="Italic">Gossypium</Emphasis> and <Emphasis Type="Italic">GhSnRK2.6</Emphasis> Improved Salt Tolerance in Transgenic Upland Cotton and <Emphasis Type="Italic">Arabidopsis</Emphasis>

SnRK2s are a large family of plant-specific protein kinases, which play important roles in multiple abiotic stress responses in various plant species. But the family in Gossypium has not been well studied. Here, we identified 13, 10, and 13 members of the SnRK2 family from Gossypium raimondii, Gossypium arboreum, and Gossypium hirsutum, respectively, and analyzed the locations of SnRK2 homologs in chromosomes based on genome data of cotton species. Phylogenetic tree analysis of SnRK2 proteins showed that these families were classified into three groups. All SnRK2 genes were comprised of nine exons and eight introns, and the exon distributions and the intron phase of homolog genes among different cotton species were analogous. Moreover, GhSnRK2.6 was overexpressed in Arabidopsis and upland cotton, respectively. Under salt treatment, overexpressed Arabidopsis could maintain higher biomass accumulation than wild-type plants, and GhSnRK2.6 overexpression in cotton exhibited higher germination rate than the control. So, the gene GhSnRK2.6 could be utilized in cotton breeding for salt tolerance.     

Assessing the monophyly of polyploid Gossypium species

The origin and monophyly of the polyploid cotton (Gossypium) species has been largely accepted, despite the lack of explicit phylogenetic evidence. Recent studies in other polyploid systems have demonstrated that multiple origins for polyploid species are much more common than once thought, raising the possibility that Gossypium polyploids also had multiple origins, as postulated by some authors. To test the monophyly of polyploid cotton, we sequenced a 2.8-kb intergenic region from all diploid species belonging to the genome groups from which the polyploid originates. The resulting phylogenetic analyses strongly support a single origin of polyploid cotton involving a D-genome ancestor related to Gossypium raimondii and an A-genome ancestor that was sister to both extant A-genome species.     

Pros and cons of using genomic SSRs and EST-SSRs for resolving phylogeny of the genus Gossypium

The genus Gossypium is comprised of 50 diverse cotton species representing eight different genomes (A through G and K), however, phylogenetic relationship using various DNA marker types such as RAPD and SSRs was determined on limited number of cotton species. In this report, we have demonstrated the application of genomic SSRs (gSSRs) and EST-SSRs, and after combining both the data sets, for resolving the phylogenies of 36 cotton species including seven races. Out of the 100 primer pairs surveyed (50 for gSSRs and 50 for EST-SSRs), 75 produced scorable amplification products in all species. Out of these, 73 were found to be polymorphic and amplified 135 alleles ranging from 1 to 5 alleles per SSR marker (average 2.87 alleles per marker). The gSSRs amplified higher number of alleles (72) compared to the EST-SSRs (63). In total 22 highly informative SSRs with PIC values ≥0.5 were identified. Genomic SSRs containing di-while EST-SSRs containing tri-nucleotide repeats exhibited high polymorphism compared to the other nucleotide repeats containing gSSRs/EST-SSRs. Number of tandem repeats and polymorphism were positively correlated. Neither the type of chromosome nor the location of the SSRs showed association with the polymorphism. Gossypium herbaceum var. africanum (Watt) Hutch. ex and Ghose and Gossypium robinsonii F. Muell. were found the most genetically diverse, while among races of Gossypium hirsutum L. “yucatanense” and G. hirsutum “punctatum” were found genetically diverse. Of the three data sets, clustering analysis based on EST-SSRs and combined data sets, revealed parallel results reported in earlier studies. This study further confirmed that Gossypium darwinii Watt has close relationship with Gossypium barbadense L. Moreover, Gossypium raimondii Ulbr. and G. herbaceum/Gossypium arboreum L. are close living relatives of the ancestor allotetraploid species. Our studies suggest that for resolving phylogenetic relationship among the various plant species EST-SSRs could be a better choice. This information can be instrumental in transferring novel alleles or loci from the wild species into the cultivated cotton species which would set a stage for cultivating genetically diverse cultivars—a way to achieve sustainable cotton production in changing climate.     

Duplication,divergence and persistence in the Phytochrome photoreceptor gene family of cottons (<Emphasis Type="Italic">Gossypium</Emphasis> spp.)

Background  

Phytochromes are a family of red/far-red photoreceptors that regulate a number of important developmental traits in cotton (Gossypium spp.), including plant architecture, fiber development, and photoperiodic flowering. Little is known about the composition and evolution of the phytochrome gene family in diploid (G. herbaceum, G. raimondii) or allotetraploid (G. hirsutum, G. barbadense) cotton species. The objective of this study was to obtain a preliminary inventory and molecular-evolutionary characterization of the phytochrome gene family in cotton.     

Cross-species transferability of G. arboreum-derived EST-SSRs in the diploid species of Gossypium

Diploid species with a common Gossypium origin are highly diverse in morphology and have been classified into eight genomic groups designated A–G and K. In this study, the transferability of 207 Gossypium arboreum-derived expressed sequence tag-simple sequence repeat (EST-SSR) primer pairs was examined among 25 different diploid accessions representing 7 genomes and 23 Gossypium species. We found that 124 of the 207 (60%) primer pairs produced amplification products in all 25 accessions. The remaining 83 (40%) primer pairs produced amplification in only a subset of species, ranging from 13 to 22 species, which is consistent with some genome- and species-specific amplification. The cross-species amplification of these EST-SSRs in 22 diploid species was 96.5% in 4,554 combinations (207 SSRs×22 species), indicative of a high transferability among the Gossypium species. Furthermore, a high level of polymorphism with an average number of 6.53 alleles per SSR marker was detected. No correlation was found between the repeat motif type and cross-species amplification. DNA sequencing showed that the high-level polymorphism findings was mainly due to changes in the number of repeat motifs and that the high transferability can be attributed to a higher-level conservation in the flanking regions among these diploid Gossypium species. The transferability among these different diploid species presented here can increase the efficiency of transferring genetic information across species and further enhance their introgression into cultivated cotton species by the molecular tagging of important genes existing in these diploid species using the EST-SSR markers.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Genetic relationships in hibiscus sect. Furcaria

The eighteen species studied form an allopolyploid series (x=18). The morphology, crossing behavior, and geographical distribution of 6 diploid, 9 tetraploid, 2 octoploid, and 1 decaploid species were studied. From over 26,500 crosses, 19 hybrid combinations and several derived allopolyploids and three-species hybrids were obtained. Chromosome pairing in the hybrids showed that a minimum of 6 and a maximum of 14 well-differentiated genome groups exist in sect. Furcaia, at least two of which appear to be confined to the Old World. No evidence was found that New World genomes are represented in the Old World. The primary radiation of the diploid genomes probably occurred at about the same time as that of the diploid genomes of Gossypium, whereas the tetraploids and one of the octoploid species (H. furcatus Roxb., non Willd.) seem to be of later origin (late Pleistocene or Recent). Octoploid H. diversifolius Jacq., a circumtropical species, may be a relict of a much earlier round of polyploid evolution.     

Clustering, haplotype diversity and locations of MIC-3: a unique root-specific defense-related gene family in Upland cotton (Gossypium hirsutum L.)

MIC-3 is a recently identified gene family shown to exhibit increased root-specific expression following nematode infection of cotton plants that are resistant to root-knot nematode. Here, we cloned and sequenced MIC-3 genes from selected diploid and tetraploid cotton species to reveal sequence differences at the molecular level and identify chromosomal locations of MIC-3 genes in Gossypium species. Detailed sequence analysis and phylogenetic clustering of MIC-3 genes indicated the presence of multiple MIC-3 gene members in Gossypium species. Haplotypes of a MIC-3 gene family member were discovered by comparative analysis among consensus sequences across genotypes within an individual clade in the phylogram to overcome the problem of duplicated loci in the tetraploid cotton. Deficiency tests of the SNPs delimited six A_t-genome members of the MIC-3 family clustered to chromosome arm 4sh, and one D_t-genome member to chromosome 19. Clustering was confirmed by long-PCR amplification of the intergenic regions using A_t-genome-specific MIC-3 primer pairs. The clustered distribution may have been favored by selection for responsiveness to evolving disease and/or pest pressures, because large variants of the MIC-3 gene family may have been recovered from small physical areas by recombination. This could give a buffer against selection pressure from a broad range of pest and pathogens in the future. To our knowledge, these are the first results on the evolution of clustering and genome-specific haplotype members of a unique cotton gene family associated with resistant response against a major pathogen.     

Salt‐tolerance diversity in diploid and polyploid cotton (Gossypium) species

The development of salt‐tolerant genotypes is pivotal for the effective utilization of salinized land and to increase global crop productivity. Several cotton species comprise the most important source of textile fibers globally, and these are increasingly grown on marginal or increasingly saline agroecosystems. The allopolyploid cotton species also provide a model system for polyploid research, of relevance here because polyploidy was suggested to be associated with increased adaptation to stress. To evaluate the genetic variation of salt tolerance among cotton species, 17 diverse accessions of allopolyploid (AD‐genome) and diploid (A‐ and D‐genome) Gossypium were evaluated for a total of 29 morphological and physiological traits associated with salt tolerance. For most morphological and physiological traits, cotton accessions showed highly variable responses to 2 weeks of exposure to moderate (50 mm NaCl) and high (100 mm NaCl) hydroponic salinity treatments. Our results showed that the most salt‐tolerant species were the allopolyploid Gossypium mustelinum from north‐east Brazil, the D‐genome diploid Gossypium klotzschianum from the Galapagos Islands, followed by the A‐genome diploids of Africa and Asia. Generally, A‐genome accessions outperformed D‐genome cottons under salinity conditions. Allopolyploid accessions from either diploid genomic group did not show significant differences in salt tolerance, but they were more similar to one of the two progenitor lineages. Our findings demonstrate that allopolyploidy in itself need not be associated with increased salinity stress tolerance and provide information for using the secondary Gossypium gene pool to breed for improved salt tolerance.     

Molecular evolution of the clustered <Emphasis Type="Italic">MIC</Emphasis>-<Emphasis Type="Italic">3</Emphasis> multigene family of <Emphasis Type="Italic">Gossypium</Emphasis> species

The Gossypium MIC-3 (Meloidogyne Induced Cotton-3) gene family is of great interest for molecular evolutionary studies because of its uniqueness to Gossypium species, multi-gene content, clustered localization, and root-knot nematode resistance-associated features. Molecular evolution of the MIC-3 gene family was studied in 15 tetraploid and diploid Gossypium genotypes that collectively represent seven phylogenetically distinct genomes. Synonymous (d_S) and non-synonymous (d_N) nucleotide substitution rates suggest that the second of the two exons of the MIC-3 genes has been under strong positive selection pressure, while the first exon has been under strong purifying selection to preserve function. Based on nucleotide substitution rates, we conclude that MIC-3 genes are evolving by a birth-and-death process and that a ‘gene amplification’ mechanism has helped to retain all duplicate copies, which best fits with the “bait and switch” model of R-gene evolution. The data indicate MIC-3 gene duplication events occurred at various rates, once per 1 million years (MY) in the allotetraploids, once per ~2 MY in the A/F genome clade, and once per ~8 MY in the D-genome clade. Variations in the MIC-3 gene family seem to reflect evolutionary selection for increased functional stability, while also expanding the capacity to develop novel “switch” pockets for responding to diverse pests and pathogens. Such evolutionary roles are congruent with the hypothesis that members of this unique resistance gene family provide fitness advantages in Gossypium.     

Phylogenetic diversity and relationship among Gossypium germplasm using SSRs markers

Gossypium species represent a vast resource of genetic multiplicity for the improvement of cultivated cotton. To determine genetic diversity and relationships within a diverse collection of Gossypium, we employed 120 SSR primers on 20 diploid species representing seven basic genome groups of the genus Gossypium, five AD allotetraploid cotton accessions while T. populnea served as an outgroup species. Out of 120 SSR primers, 49 pairs are polymorphic, which produced a total of 99 distinct alleles with an average of 2.0 alleles per primer pair. A total of 1139 major SSR bands were observed. Genetic similarities among all the diploid species ranged from 0.582 (between G. herbaceum and G. trilobum) up to 0.969 (between G. arboreum and G. herbaceum). Phylogenetic trees based on genetic similarities were consistent with known taxonomic relationships. The results also indicated that G. raimondii is the closest living relative of the ancestral D-genome donor of tetraploid species and the A-genome donor is much similar to the present-day G. herbaceum and G. arboreum. Ancient tetraploid cotton species were formed by hybridizing and chromosome doubling between them, then different tetraploid cotton species appeared by further geographical and genetic isolation and separating differentiation. The results showed that SSRs could be an ideal means for the identification of the genetic diversity and relationship of cotton resources at the genomic level.     

Extensive and Biased Intergenomic Nonreciprocal DNA Exchanges Shaped a Nascent Polyploid Genome,Gossypium (Cotton)

Genome duplication is thought to be central to the evolution of morphological complexity, and some polyploids enjoy a variety of capabilities that transgress those of their diploid progenitors. Comparison of genomic sequences from several tetraploid (A_tD_t) Gossypium species and genotypes with putative diploid A- and D-genome progenitor species revealed that unidirectional DNA exchanges between homeologous chromosomes were the predominant mechanism responsible for allelic differences between the Gossypium tetraploids and their diploid progenitors. Homeologous gene conversion events (HeGCEs) gradually subsided, declining to rates similar to random mutation during radiation of the polyploid into multiple clades and species. Despite occurring in a common nucleus, preservation of HeGCE is asymmetric in the two tetraploid subgenomes. A_t-to-D_t conversion is far more abundant than the reciprocal, is enriched in heterochromatin, is highly correlated with GC content and transposon distribution, and may silence abundant A-genome-derived retrotransposons. D_t-to-A_t conversion is abundant in euchromatin and genes, frequently reversing losses of gene function. The long-standing observation that the nonspinnable-fibered D-genome contributes to the superior yield and quality of tetraploid cotton fibers may be explained by accelerated D_t to A_t conversion during cotton domestication and improvement, increasing dosage of alleles from the spinnable-fibered A-genome. HeGCE may provide an alternative to (rare) reciprocal DNA exchanges between chromosomes in heterochromatin, where genes have approximately five times greater abundance of D_t-to-A_t conversion than does adjacent intergenic DNA. Spanning exon-to-gene-sized regions, HeGCE is a natural noninvasive means of gene transfer with the precision of transformation, potentially important in genetic improvement of many crop plants.     

miR482 Regulation of NBS-LRR Defense Genes during Fungal Pathogen Infection in Cotton

In this study, we characterized the miR482 family in cotton using existing small RNA datasets and the recently released draft genome sequence of Gossypium raimondii, a diploid cotton species whose progenitor is the putative contributor of the D_t (representing the D genome of tetraploid) genome of the cultivated tetraploid cotton species G. hirsutum and G. barbadense. Of the three ghr-miR482 members reported in G. hirsutum, ghr-miR482a has no homolog in G. raimondii, ghr-miR482b and ghr-miR482c each has a single homolog in G. raimondii. Gra-miR482d has five homologous loci (gra-miR482d, f-i) in G. raimondii and also exists in G. hirsutum (ghr-miR482d). A variant, miR482.2 that is a homolog of miR2118 in other species, is produced from several GHR-MIR482 loci in G. hirsutum. Approximately 12% of the G. raimondii NBS-LRR genes were predicted targets of various members of the gra-miR482 family. Based on the rationale that the regulatory relationship between miR482 and NBS-LRR genes will be conserved in G. raimondii and G. hirsutum, we investigated this relationship using G. hirsutum miR482 and G. raimondii NBS-LRR genes, which are not currently available in G. hirsutum. Ghr-miR482/miR482.2-mediated cleavage was confirmed for three of the four NBS-LRR genes analysed. As in tomato, miR482-mediated cleavage of NBS-LRR genes triggered production of phased secondary small RNAs in cotton. In seedlings of the susceptible cultivar Sicot71 (G. hirsutum) infected with the fungal pathogen Verticillium dahliae, the expression levels of ghr-miR482b/miR482b.2, ghr-miR482c and ghr-miR482d.2 were down-regulated, and several NBS-LRR targets of ghr-miR482c and ghr-miR482d were up-regulated. These results imply that, like tomato plants infected with viruses or bacteria, cotton plants are able to induce expression of NBS-LRR defence genes by suppression of the miRNA-mediated gene silencing pathway upon fungal pathogen attack.     

A New Synthetic Allotetraploid (A1A1G2G2) between Gossypium herbaceum and G. australe: Bridging for Simultaneously Transferring Favorable Genes from These Two Diploid Species into Upland Cotton

Gossypium herbaceum, a cultivated diploid cotton species (2n = 2x = 26, A₁A₁), has favorable traits such as excellent drought tolerance and resistance to sucking insects and leaf curl virus. G. australe, a wild diploid cotton species (2n = 2x = 26, G₂G₂), possesses numerous economically valuable characteristics such as delayed pigment gland morphogenesis (which is conducive to the production of seeds with very low levels of gossypol as a potential food source for humans and animals) and resistance to insects, wilt diseases and abiotic stress. Creating synthetic allotetraploid cotton from these two species would lay the foundation for simultaneously transferring favorable genes into cultivated tetraploid cotton. Here, we crossed G. herbaceum (as the maternal parent) with G. australe to produce an F₁ interspecific hybrid and doubled its chromosome complement with colchicine, successfully generating a synthetic tetraploid. The obtained tetraploid was confirmed by morphology, cytology and molecular markers and then self-pollinated. The S₁ seedlings derived from this tetraploid gradually became flavescent after emergence of the fifth true leaf, but they were rescued by grafting and produced S₂ seeds. The rescued S₁ plants were partially fertile due to the existence of univalents at Metaphase I of meiosis, leading to the formation of unbalanced, nonviable gametes lacking complete sets of chromosomes. The S₂ plants grew well and no flavescence was observed, implying that interspecific incompatibility, to some extent, had been alleviated in the S₂ generation. The synthetic allotetraploid will be quite useful for polyploidy evolutionary studies and as a bridge for transferring favorable genes from these two diploid species into Upland cotton through hybridization.     

Development of chromosome-specific markers with high polymorphism for allotetraploid cotton based on genome-wide characterization of simple sequence repeats in diploid cottons (Gossypium arboreum L. and Gossypium raimondii Ulbrich)

Background

Tetraploid cotton contains two sets of homologous chromosomes, the At- and Dt-subgenomes. Consequently, many markers in cotton were mapped to multiple positions during linkage genetic map construction, posing a challenge to anchoring linkage groups and mapping economically-important genes to particular chromosomes. Chromosome-specific markers could solve this problem. Recently, the genomes of two diploid species were sequenced whose progenitors were putative contributors of the At- and Dt-subgenomes to tetraploid cotton. These sequences provide a powerful tool for developing chromosome-specific markers given the high level of synteny among tetraploid and diploid cotton genomes. In this study, simple sequence repeats (SSRs) on each chromosome in the two diploid genomes were characterized. Chromosome-specific SSRs were developed by comparative analysis and proved to distinguish chromosomes.

Results

A total of 200,744 and 142,409 SSRs were detected on the 13 chromosomes of Gossypium arboreum L. and Gossypium raimondii Ulbrich, respectively. Chromosome-specific SSRs were obtained by comparing SSR flanking sequences from each chromosome with those from the other 25 chromosomes. The average was 7,996 per chromosome. To confirm their chromosome specificity, these SSRs were used to distinguish two homologous chromosomes in tetraploid cotton through linkage group construction. The chromosome-specific SSRs and previously-reported chromosome markers were grouped together, and no marker mapped to another homologous chromosome, proving that the chromosome-specific SSRs were unique and could distinguish homologous chromosomes in tetraploid cotton. Because longer dinucleotide AT-rich repeats were the most polymorphic in previous reports, the SSRs on each chromosome were sorted by motif type and repeat length for convenient selection. The primer sequences of all chromosome-specific SSRs were also made publicly available.

Conclusion

Chromosome-specific SSRs are efficient tools for chromosome identification by anchoring linkage groups to particular chromosomes during genetic mapping and are especially useful in mapping of qualitative-trait genes or quantitative trait loci with just a few markers. The SSRs reported here will facilitate a number of genetic and genomic studies in cotton, including construction of high-density genetic maps, positional gene cloning, fingerprinting, and genetic diversity and comparative evolutionary analyses among Gossypium species.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1265-2) contains supplementary material, which is available to authorized users.     

Copy number lability and evolutionary dynamics of the Adh gene family in diploid and tetraploid cotton (Gossypium)

Nuclear-encoded genes exist in families of various sizes. To further our understanding of the evolutionary dynamics of nuclear gene families we present a characterization of the structure and evolution of the alcohol dehydrogenase (Adh) gene family in diploid and tetraploid members of the cotton genus (Gossypium, Malvaceae). A PCR-based approach was employed to isolate and sequence multiple Adh gene family members, and Southern hybridization analyses were used to document variation in gene copy number. Adh gene copy number varies among Gossypium species, with diploids containing at least seven Adh loci in two primary gene lineages. Allotetraploid Gossypium species are inferred to contain at least 14 loci. Intron lengths vary markedly between loci, and one locus has lost two introns usually found in other plant Adh genes. Multiple examples of apparent gene duplication events were observed and at least one case of pseudogenization and one case of gene elimination were also found. Thus, Adh gene family structure is dynamic within this single plant genus. Evolutionary rate estimates differ between loci and in some cases between organismal lineages at the same locus. We suggest that dynamic fluctuation in copy number will prove common for nuclear genes, and we discuss the implications of this perspective for inferences of orthology and functional evolution.     

Analysis of [Gossypium capitis-viridis × (G.hirsutum × G.australe)2] Trispecific Hybrid and Selected Characteristics

Speciation is always a contentious and challenging issue following with the presence of gene flow. In Gossypium, there are many valuable resources and wild diploid cotton especially C and B genome species possess some excellent traits which cultivated cotton always lacks. In order to explore character transferring rule from wild cotton to upland tetraploid cotton, the [G. capitis-viridis × (G. hirsutum × G. australe)²] triple hybrid was synthesized by interspecies hybridization and chromosome doubling. Morphology comparisons were measured among this hybrid and its parents. It showed that trispecific hybrid F₁ had some intermediate morphological characters like leaf style between its parents and some different characters from its parents, like crawl growth characteristics and two kind flower color. It is highly resistant to insects comparing with other cotton species by four year field investigation. By cytogenetic analysis, triple hybrid was further confirmed by meiosis behavior of pollen mother cells. Comparing with regular meiosis of its three parents, it was distinguished by the occurrence of polyads with various numbers of unbalanced microspores and finally generating various abnormal pollen grains. All this phenomenon results in the sterility of this hybrid. This hybrid was further identified by SSR marker from DNA molecular level. It showed that 98 selected polymorphism primers amplified effective bands in this hybrids and its parents. The genetic proportion of three parents in this hybrid is 47.8% from G. hirsutum, 14.3% from G. australe, 7.0% from G. capitis-viridis, and 30.9% recombination bands respectively. It was testified that wild genetic material has been transferred into cultivated cotton and this new germplasm can be incorporated into cotton breeding program.     

雷蒙德氏棉和亚洲棉基因组数据中LPAAT基因家族的发掘及其同源基因在陆地棉材料中的表达分析

溶血磷脂酸酰基转移酶(Lysophosphatidic acid acyltransferase, LPAAT)是油脂合成途径中的一个关键酶,能催化溶血磷脂酸转变为磷脂酸。本研究从雷蒙德氏棉(G. raimondii, D5)和亚洲棉(G. arboreum, A2)的基因组数据中得到17个LPAAT基因家族成员。利用生物信息学方法对二倍体棉花LPAAT基因进行基因结构、染色体分布以及系统进化分析。结果表明,LPAAT基因家族根据亲缘关系的远近可以分为不同的亚家族,各亚家族中LPAAT基因具有相似的基因结构;LPAAT家族基因编码的氨基酸序列具有3个保守基序,其中包括ΦFPEGTR-G结合位点和Φ-NHQS-ΦDΦΦ催化位点;通过对不同物种的LPAAT基因家族进行系统进化分析可知,不同物种中的LPAAT在进化中存在较大差异。基于陆地棉(G. hirsutum)不同发育时期的胚珠RNA-seq数据库和qRT-PCR表达分析,发现LPAAT基因可能对脂肪积累起到积极作用。本研究结果有助于了解棉属植物LPAAT基因家族的功能,以期从中选取较好的LPAAT基因进行进一步功能验证。