Food attraction and population growth of fungivorous nematodes with different fungi

Food attraction of the fungivorous nematodes Aphelenchus avenae and Aphelenchoides spp. to seven fungal species (Pyrenochaeta lycopersici, Botrytis cinerea, Rhizoctonia solani strains AG 3 and AG 2‐1, Verticillium dahliae, Pochonia bulbillosa, Mortierella hyalina and Trichoderma harzianum) was determined on agar plates by counting the number of test nematodes present on the mycelium of each fungus 24 h after inoculation. Population growth of A. avenae and Aphelenchoides spp. on five of the seven fungi included in the attraction test (P. lycopersici, R. solani strain AG 3, V. dahliae, P. bulbillosa and T. harzianum) was also determined on agar plates by counting nematode numbers every week during a 6‐week period. A. avenae and Aphelenchoides spp. were attracted to all the fungi tested. A. avenae was preferentially attracted to V. dahliae (P < 0.0001), and Aphelenchoides spp. did not show any preference except for low attraction to R. solani. A. avenae and Aphelenchoides spp. reproduced on all fungal species tested. After 6 weeks of incubation, the highest number of nematodes was found on P. lycopersici and P. bulbillosa, while the lowest number occurred on R. solani for A. avenae and on T. harzianum for Aphelenchoides spp. The suitability of a fungus as a host was not clearly related to the attraction to that fungus.     

H9, H10, and H11 compose a cluster of Hessian fly-resistance genes in the distal gene-rich region of wheat chromosome 1AS

H9, H10, and H11 are major dominant resistance genes in wheat, expressing antibiosis against Hessian fly [(Hf) Mayetiola destructor (Say)] larvae. Previously, H9 and H10 were assigned to chromosome 5A and H11 to 1A. The objectives of this study were to identify simple-sequence-repeat (SSR) markers for fine mapping of these genes and for marker-assisted selection in wheat breeding. Contrary to previous results, H9 and H10 did not show linkage with SSR markers on chromosome 5A. Instead, H9, H10, and H11 are linked with SSR markers on the short arm of chromosome 1A. Both H9 and H10 are tightly linked to flanking markers Xbarc263 and Xcfa2153 within a genetic distance of 0.3–0.5 cM. H11 is tightly linked to flanking markers Xcfa2153 and Xbarc263 at genetic distances of 0.3 cM and 1.7 cM. Deletion bin mapping assigned these markers and genes to the distal 14% of chromosome arm 1AS, where another Hf-resistance gene, Hdic (derived from emmer wheat), was also mapped previously. Marker polymorphism results indicated that a small terminal segment of chromosome 1AS containing H9 or H10 was transferred from the donor parent to the wheat lines Iris or Joy, and a small intercalary fragment carrying H11 was transferred from the resistant donor to the wheat line Karen. Our results suggest that H9, H10, H11, Hdic, and the previously identified H9- or H11-linked genes (H3, H5, H6, H12, H14, H15, H16, H17, H19, H28, and H29) may compose a cluster (or family) of Hf-resistance genes in the distal gene-rich region of wheat chromosome 1AS; and H10 most likely is the same gene as H9.Mention of commercial or proprietary product does not constitute an endorsement by the USDA.     

Identification of SNPs and development of functional markers for LMW-GS genes at <Emphasis Type="Italic">Glu-D3</Emphasis> and <Emphasis Type="Italic">Glu-B3</Emphasis> loci in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Low-molecular-weight glutenin subunits (LMW-GS) have great effect on wheat processing quality, but were numerous and difficult to dissect by SDS-PAGE. The development of functional markers may be the most effective way for a clear discrimination of different LMW-GS genes. In the present study, three different approaches were used to identify SNPs of different genes at Glu-D3 and Glu-B3 loci in bread wheat for the development of six STS markers (3 for Glu-D3 and 3 for Glu-B3 genes) that were validated with distinguished wheat cultivars. Firstly, seven LMW-GS gene sequences ( AY585350, AY585354, AY585355, AY585356, AY585349, AY585351 and AY585353 ) from Aegilops tauschii, the diploid donor of the D-genome of bread wheat, were chosen to design seven pairs of AS-PCR primers for Glu-D3 genes. By amplifying the corresponding genes from five bread wheat cultivars with different Glu-D3 alleles (a, b, c, d and e) and Ae. tauschii, a primer set, S13F2/S13R1, specific to the gene AY585356, was found to be positive to cultivars with alleles Glu-D3c and d. Nevertheless, the other five pairs of primers designed from AY585350, AY585349, AY585353, AY585354 and AY585355, respectively, did not produce specific PCR products to the cultivars tested. Secondly, all the PCR products from the five primer sets without specific characteristics were sequenced and an SNP from the gene AY585350 was detected in the cultivar Hartog, which resulted in the second STS marker S1F1/S1R3 specific to the allelic variant of AY585350. Thirdly, three Glu-D3 sequences (AB062851, AB062865 and AB062872) and three Glu-B3 sequences (AB062852, AB062853 and AB062860) defined by Ikeda et al. (2002) were chosen to query wheat EST and NR databases, and DNA markers were developed based on the putative SNPs among the sequences. Using this approach, four STS markers were developed and validated with 16-19 bread wheat cultivars. The primer set T1F4/T1R1 was also a Glu-D3 gene-specific marker for AB062872, while T2F2/T2R2, T5F3/T5R1 and T13F4/T13R3 were all Glu-B3 gene specific markers for AB062852, BF293671 and AY831800, respectively. The chromosomal locations of the six markers were verified by amplifying the genomic DNA of Ae. tauschii (DD), T. monococcum (AA) and T. turgidum (AABB) entries, as well as Chinese Spring and its group 1 chromosome nulli-tetrasomic lines. The results are useful to discriminate the corresponding Glu-D3 and Glu-B3 genes in wheat breeding programs.     

Taxonomic review of the genus Lymantria (Lepidoptera: Erebidae: Lymantriinae) in Korea

A taxonomic review of the Korean Lymantria Hübner, 1819 was conducted. A total of nine species of five subgenera with two unrecorded species are listed: Lymantria (Porthetria) dispar Linnaeus 1758, L. (P.) xylina Swinhoe 1903, L. (Lymantria) monacha (Linnaeus 1758), L. (L.) minomonis Matsumura 1933 (new to Korea), L. (L.) similis monachoides Schintlimeister 2004 (new to Korea), L. (L.) lucescens (Butler 1881), L. (Nyctria) mathura Moore 1865, L. (Collentria) fumida Butler 1877, and L. (Spinotria) bantaizana Matsumura 1933. Lymantria (Lymantria) minomonis and L. (L.) similis monachoides are newly added to the Korean fauna. Lymantria (L.) minomonis was found only on Bogildo Island of Jeollanam‐do in the southern part of Korea, and L. (L.) similis monachoides was collected in central Korea. Lymantria (Porthetria) xylina and L. (Collentria) fumida were not examined in this study, and it is considered that the previous records were due to misidentification or they are only distributed in the northern part of the Korean Peninsula. We provide diagnoses of two unrecorded species and adult habitus and genitalia photos of the Korean Lymantria species.     

Quantitative disease resistance to the bacterial pathogen Xanthomonas campestris involves an Arabidopsis immune receptor pair and a gene of unknown function

Although quantitative disease resistance (QDR) is a durable and broad‐spectrum form of resistance in plants, the identification of the genes underlying QDR is still in its infancy. RKS1 (Resistance related KinaSe1) has been reported recently to confer QDR in Arabidopsis thaliana to most but not all races of the bacterial pathogen Xanthomonas campestris pv. campestris (Xcc). We therefore explored the genetic bases of QDR in A. thaliana to diverse races of X. campestris (Xc). A nested genome‐wide association mapping approach was used to finely map the genomic regions associated with QDR to Xcc12824 (race 2) and XccCFBP6943 (race 6). To identify the gene(s) implicated in QDR, insertional mutants (T‐DNA) were selected for the candidate genes and phenotyped in response to Xc. We identified two major QTLs that confer resistance specifically to Xcc12824 and XccCFBP6943. Although QDR to Xcc12824 is conferred by At5g22540 encoding for a protein of unknown function, QDR to XccCFBP6943 involves the well‐known immune receptor pair RRS1/RPS4. In addition to RKS1, this study reveals that three genes are involved in resistance to Xc with strikingly different ranges of specificity, suggesting that QDR to Xc involves a complex network integrating multiple response pathways triggered by distinct pathogen molecular determinants.     

The enemy of my enemy is still my enemy: competitors add to predator load of a tree‐killing bark beetle

1 The mountain pine beetle Dendroctonus ponderosae is a major tree‐killing bark beetle in North America. We evaluated how the subsequent arrival of a competing bark beetle Ips pini influences the arrival of predators and their impact on both species. 2 The predators Temnochila chlorodia and Enoclerus sphegeus were strongly attracted to pheromones of D. ponderosae. By contrast, Enoclerus lecontei was mostly attracted to I. pini pheromones. The host compound myrcene synergized attraction of both D. ponderosae and E. sphegeus to the pheromone of D. ponderosae. However, it inhibited attraction of both I. pini and E. lecontei to I. pini’s pheromone. 3 Dendroctonus ponderosae were more attracted to trees than logs treated with its pheromones, whereas I. pini were more attracted to logs than trees treated with its pheromones. Some 78% of T. chlorodia were captured at hosts baited with D. ponderosae pheromones, whereas 83% of E. lecontei were captured at hosts baited with I. pini pheromones. We characterized the sequence of arrival to live trees baited with pheromones of D. ponderosae as: D. ponderosae, T. chlorodia, E. sphegeus, I. pini, E. lecontei. 4 Various combinations of I. pini and predators were added to logs colonized by D. ponderosae in the above sequence of arrival observed in live trees baited with D. ponderosae aggregation pheromones. Ips pini reduced D. ponderosae adult brood production. However, the combination of I. pini and E. lecontei did not raise D. ponderosae brood production above that observed with only I. pini present. Similarly, the combination of I. pini and T. chlorodia did not reduce D. ponderosae brood production below that observed with I. pini alone. By contrast, the combination of I. pini, T. chlorodia and E. lecontei caused more brood loss to D. ponderosae than I. pini alone. 5 Enoclerus lecontei did not reduce brood production by T. chlorodia, whereas T. chlorodia substantially reduced brood production by E. lecontei. 6 Secondary bark beetles that exploit the resource created by primary tree‐killing species exert negative effects through both competition and increased predator load. Implications to the population dynamics, ecology and evolution of tree‐killing bark beetles are discussed.     

Inflorescence development in the Vitis–Ampelocissus clade of Vitaceae: the unusual lamellate inflorescence of Pterisanthes

Pterisanthes (Vitaceae) is a genus of c. 20 species of scandent climbers endemic to Southeast Asia with unusual lamellate inflorescences. Molecular phylogenetic analysis supports its relationship in the well‐supported Vitis–Ampelocissus–Nothocissus–Pterisanthes clade (i.e. the Ampelocissus–Vitis clade). Shoot tips and floral buds were collected from wild and greenhouse‐grown P. eriopoda at different developmental stages and were examined using epi‐illumination, light and scanning electron microscopy. Inflorescence and floral ontogeny was studied to discover how the lamellate inflorescence evolved and to make morphological comparisons to infer relationships with closely related members of Vitaceae. The second‐order branches in P. eriopoda are racemose and develop helically around the inflorescence axis in a similar fashion to Vitis and Ampelocissus. Inflorescence branching is restricted to the second order in P. eriopoda, whereas in Vitis and most Ampelocissus species subsequent branching orders culminate in the typical vitaceous determinate dichasium. In P. eriopoda subsequent lateral growth of the second‐order branches combined with the inhibition of peduncle or pedicel formation and loss of dichasial branching results in the unique lamellae in Pterisanthes, on which the floral primordia arise directly in a helical pattern. Floral development in P. eriopoda is the same as in other genera of Vitaceae examined to date with initiation of floral whorls centripetally, the calyx ring developing first and calyx lobes fused to cover the petals and stamen primordia. Given the recent phylogenetic results that placed Pterisanthes firmly within Ampelocissus, the most likely scenario is that the Pterisanthes inflorescence is derived from the thyrse of an Ampelocissus‐like ancestor and that the thyrse is a morphological synapomorphy of the Ampelocissus–Vitis clade. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 725–741.     

Analysis of S-RNase alleles of almond (Prunus dulcis): characterization of new sequences, resolution of synonyms and evidence of intragenic recombination

Cross-compatibility relationships in almond are controlled by a gametophytically expressed incompatibility system partly mediated by stylar RNases, of which 29 have been reported. To resolve possible synonyms and to provide data for phylogenetic analysis, 21 almond S-RNase alleles were cloned and sequenced from SP (signal peptide region) or C1 (first conserved region) to C5, except for the S ₂₉ allele, which could be cloned only from SP to C1. Nineteen sequences (S ₄ , S ₆ , S ₁₁ –S ₂₂ , S ₂₅ –S ₂₉ ) were potentially new whereas S ₁₀ and S ₂₄ had previously been published but with different labels. The sequences for S ₁₆ and S ₁₇ were identical to that for S ₁ , published previously; likewise, S ₁₅ was identical to S ₅ . In addition, S ₄ and S ₂₀ were identical, as were S ₁₃ and S ₁₉ . A revised version of the standard table of almond incompatibility genotypes is presented. Several alleles had AT or GA tandem repeats in their introns. Sequences of the 23 distinct newly cloned or already published alleles were aligned. Sliding windows analysis of Ka/Ks identified regions where positive selection may operate; in contrast to the Maloideae, most of the region from the beginning of C3 to the beginning of RC4 appeared not to be under positive selection. Phylogenetic analysis indicated four pairs of alleles had ‘bootstrap’ support > 80%: S ₅ /S ₁₀ , S ₄ /S _8, S ₁₁ /S ₂₄ , and S ₃ /S ₆ . Various motifs up to 19 residues long occurred in at least two alleles, and their distributions were consistent with intragenic recombination, as were separate phylogenetic analyses of the 5′ and 3′ sections. Sequence comparison of phylogenetically related alleles indicated the significance of the region between RC4 and C5 in defining specificity.An erratum to this article can be found at     

The Tipulidae (Diptera) of northern Morocco with a focus on the Rif region,including the description of a new species of Tipula (Lunatipula) and an updated checklist for Morocco

An overview of the Tipulidae known to occur in northern Morocco with an emphasis on the Rif mountains is given, incorporating new distribution data based on recently collected material in the area. Dolichopeza (Dolichopeza) hispanica, Tipula (Lunatipula) subpustulata, and Tipula (Yamatotipula) afriberia afriberia are recorded for the first time for the Rif. Tipula (L.) stimulosa Mannheims, 1973 and T. (Vestiplex) vaillanti vaillanti Theowald, 1977 are reported for the first time for the Rif and Morocco. Tipula (Lunatipula) pseudocinerascens Strobl, 1906 and Tipula (Savtshenkia) confusa van der Wulp, 1883 are recorded for the first time for the Rif, Morocco and North Africa. A new species of the subgenus Lunatipula, T. (L.) pjotri n. sp., is described and illustrated. Nephrotoma exastigma, previously reported for the Rif, seems to be absent in Morocco. Reports of Tipula (Emodotipula) obscuriventris Strobl, 1900 for Morocco actually refer to T. (E.) leo. This brings the number of Tipulidae for Morocco to 39 species and for the Rif to 28. An updated checklist of the Tipulidae of Morocco is provided.     

Phylogenetic relationships within the South American fish family Anostomidae (Teleostei,Ostariophysi, Characiformes)

Analysis of a morphological dataset containing 152 parsimony‐informative characters yielded the first phylogenetic reconstruction spanning the South American characiform family Anostomidae. The reconstruction included 46 ingroup species representing all anostomid genera and subgenera. Outgroup comparisons included members of the sister group to the Anostomidae (the Chilodontidae) as well as members of the families Curimatidae, Characidae, Citharinidae, Distichodontidae, Hemiodontidae, Parodontidae and Prochilodontidae. The results supported a clade containing Anostomus, Gnathodolus, Pseudanos, Sartor and Synaptolaemus (the subfamily Anostominae sensu Winterbottom) albeit with a somewhat different set of relationships among the species within these genera. Anostomus as previously recognized was found to be paraphyletic and is split herein into two monophyletic components, a restricted Anostomus and the new genus Petulanos gen. nov. , described herein. Laemolyta appeared as sister to the clade containing Anostomus, Gnathodolus, Petulanos, Pseudanos, Sartor and Synaptolaemus. Rhytiodus and Schizodon together formed a well‐supported clade that was, in turn, sister to the clade containing Anostomus, Gnathodolus, Laemolyta, Petulanos, Pseudanos, Sartor and Synaptolaemus. Anostomoides was sister to the clade formed by these nine genera. Leporinus as currently defined was not found to be monophyletic, although certain clades within that genus were supported, including the species with subterminal mouths in the former subgenus Hypomasticus which we recognize herein as a genus. Abramites nested in Leporinus, and Leporellus was found to be the most basal anostomid genus. The presence of cis‐ and trans‐Andean species in Abramites, Leporellus, Leporinus and Schizodon, all relatively basal genera, suggests that much of the diversification of anostomid species pre‐dates the uplift of the Andean Cordilleras circa 11.8 million years ago. Several important morphological shifts in anostomid evolution are illustrated and discussed, including instances of convergence and reversal. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 70–210.     

Phylogenetic systematics of the Empis (Coptophlebia) hyalea-group (Insecta: Diptera: Empididae)

Six clades are inferred from a phylogenetic analysis including 42 species belonging to the Empis (Coptophlebia) hyalea‐group. These clades are named as follows: E. (C.) acris, E. (C.) aspina, E. (C.) atratata, E. (C.) hyalea, E. (C.) jacobsoni and E. (C.) nahaeoensis. The presence of two dorsal more or less developed epandrial projections is considered autapomorphic for the E. (C.) hyalea‐group in addition to two characters previously found to support the monophyly of this group (presence of an unsclerotized zone in the middle of labella and epandrium unpaired). Amongst the cladistically analysed species, 24 are newly described [ E. ( C. ) acris , E. ( C. ) aspina , E. ( C. ) cameronensis , E. ( C. ) duplex , E. ( C. ) incurva , E. ( C. ) inferiseta , E. ( C. ) kuaensis , E. ( C. ) lachaisei , E. ( C. ) lamellalta , E. ( C. ) lata , E. ( C. ) loici , E. ( C. ) longiseta , E. ( C. ) mengyangensis , E. ( C. ) menglunensis , E. ( C. ) missai , E. ( C. ) nimbaensis , E. ( C. ) padangensis , E. ( C. ) parvula , E. ( C. ) projecta , E. ( C. ) pseudonahaeoensis , E. ( C. ) submetallica , E. ( C. ) urumae , E. ( C. ) vitisalutatoris and E. ( C. ) woitapensis ], five are reviewed [E. (C.) hyalea Melander, E. (C.) jacobsoni De Meijere, E. (C.) ostentator Melander, E. (C.) sinensis Melander and E. (C.) thiasotes Melander] and 13 were recently described in two previous papers. Two additional species, E. (C.) abbrevinervis De Meijere and E. (C.) multipennata Melander, are also reviewed but not included in the cladistic analysis since they are only known from the female. A lectotype is designated for E. (C.) jacobsoni. A key is provided to the six clades of the E. (C.) hyalea‐group as well as to species of each clade. A catalogue of the E. (C.) hyalea‐group, including 72 species, is given. The taxonomic status of 25 additional species mainly described by Bezzi and Brunetti, from the Oriental and Australasian regions, is discussed. The E. (C.) hyalea‐group is firstly recorded from the Palaearctic Region and Australia. Finally, the distribution and the habitats of the species compared with their phylogeny suggest a possible relationship between the diversification of the group and forest fragmentations during the Quaternary. © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 145 , 339–391.     

A comparison of five distance‐based methods for spatial pattern analysis

Abstract. The behaviour of five statistics (extensions of Pielou's, Clark and Evansapos;, Pollard's, Johnson & Zimmer's, and Eberhardt's statistics, which are denoted as P_i, C_e, P_o, J_z and E_b respectively) that involve the distance from a random point to its jth nearest neighbour were examined against several alternative patterns (lattice‐based regular, inhomogeneous random, and Poisson cluster patterns) through Monte Carlo simulation to test their powers to detect patterns. The powers of all the five statistics increase as distance order j increases against inhomogeneous random pattern. They decrease for P_i and C_e and increase for P_o, J_z, and E_b against regular and Poisson cluster patterns. P_o, J_z, and E_b can reach high powers with the third or higher order distances in most cases. However, P_o is recommended because no extra information is needed, it can reach a high power with the second or third distance even though the sample size is not large in most cases, and the test can be performed with an approximate χ² distribution associated with it. When a regular pattern is expected, J_z is recommended because it is more sensitive to lattice‐based regular pattern than P_o and E_b, especially for the first distance. However, simulation tests should be used because the speed of convergence of J_z to normal distribution is very slow.     

Three members of the S multigene family are linked to the S locus of Brassica

Two self-incompatibility genes in Brassica, SLG and SRK (SLG encodes a glycoprotein; SRK encodes a receptor-like kinase), are included in the S multigene family. Products of members of the S multigene family have an SLG-like domain (S domain) in common, which may function as a receptor. In this study, three clustered members of the S multigene family, BcRK1, BcRL1 and BcSL1, were characterized. BcRK1 is a putative functional receptor kinase gene expressed in leaves, flower buds and stigmas, while BcRL1 and BcSL1 are considered to be pseudogenes because deletions causing frameshifts were identified in these sequences. Sequence and expression pattern of BcRK1 were most similar to those of the Arabidopsis receptor-like kinase gene ARK1, indicating that BcRK1 might have a function similar to that of ARK1, in processes such as cell expansion or plant growth. Interestingly, the region containing BcRK1, BcRL1 and BcSL1 is genetically linked to the S locus and the physical distance between SLG, SRK and the three S-related genes was estimated to be less than 610 kb. Thus the genes associated with self-incompatibility exist within a cluster of S-like genes in the genome of Brassica. Received: 15 April 1997 / Accepted: 13 June 1997     

RTA2, a novel gene involved in azole resistance in Candida albicans

Widespread and repeated use of azoles, particularly fluconazole, has led to the rapid development of azole resistance in Candida albicans. Overexpression of CDR1, CDR2, and CaMDR1 has been reported contributing to azole resistance in C. albicans. In this study, hyper-resistant C. albicans mutant, with the above three genes deleted, was obtained by exposure to fluconazole and fluphenezine for 28 passages. Thirty-five differentially expressed genes were identified in the hyper-resistant mutant by microarray analysis; among the 13 up-regulated genes, we successfully constructed the rta2 and ipf14030 null mutants in C. albicans strain with deletions of CDR1, CDR2 and CaMDR1. Using spot dilution assay, we demonstrated that the disruption of RTA2 increased the susceptibility of C. albicans to azoles while the disruption of IPF14030 did not influence the sensitivity of C. albicans to azoles. Meanwhile, we found that ectopic overexpression of RTA2 in C. albicans strain with deletions of CDR1, CDR2 and CaMDR1 conferred resistance to azoles. RTA2 expression was found elevated in clinical azole-resistant isolates of C. albicans. In conclusion, our findings suggest that RTA2 is involved in the development of azole resistance in C. albicans.     

Oenothera mitochondrial orf454, a gene involved in cytochrome c biogenesis corresponds to orf169 and orf322 of Marchantia

We have characterized a mitochondrial gene in Oenothera, designated orf454, capable of encoding a component of the cytochrome c biogenesis system. This open reading frame is interrupted by an intron of 941 nucleotides showing high similarity to a group II intron residing in the rpl2 gene. RNA editing, which is observed at 18 cytidine positions within the orf454 reading frame, improves the similarity to protein-coding sequences in bacteria and higher plants and removes the last 16 amino acids. orf454 also shows high sequence similarity to two overlapping reading frames (orf169 and orf322) of Marchantia mitochondria. These ORFs belong to an operon-like cluster of genes in the liverwort that is not conserved in Oenothera mitochondria. However, in bacteria these reading frames are organized like the Marchantia gene cluster. It has been shown by genetical analysis in Rhodobacter capsulatus that these genes are essential for cytochrome c biogenesis. Genes of bacterial operons — ccl1 in Rhodobacter and yejR and nrfE in Escherichia coli — show high sequence similarity to the mitochondrial reading frames orf577 and orf454 of Oenothera. orf454, which we describe here, is homologous to the C-terminal region of these bacterial genes, while the previously described orf577 is homologous to the N-terminal region.     

The miR156‐SPL9‐DFR pathway coordinates the relationship between development and abiotic stress tolerance in plants

Young organisms have relatively strong resistance to diseases and adverse conditions. When confronted with adversity, the process of development is delayed in plants. This phenomenon is thought to result from the rebalancing of energy, which helps plants to coordinate the relationship between development and stress tolerance; however, the molecular mechanism underlying this phenomenon remains mysterious. In this study, we found that miR156 integrates environmental signals to ensure timely flowering, thus enabling the completion of breeding. Under stress conditions, miR156 is induced to maintain the plant in the juvenile state for a relatively long period of time, whereas under favorable conditions, miR156 is suppressed to accelerate the developmental transition. Blocking the miR156 signaling pathway in Arabidopsis thaliana with 35S::MIM156 (via target mimicry) increased the sensitivity of the plant to stress treatment, whereas overexpression of miR156 increased stress tolerance. In fact, this mechanism is also conserved in Oryza sativa (rice). We also identified downstream genes of miR156, i.e. SQUAMOSA PROMOTER BINDING PROTEIN‐LIKE 9 (SPL9) and DIHYDROFLAVONOL‐4‐REDUCTASE (DFR), which take part in this process by influencing the metabolism of anthocyanin. Our results uncover a molecular mechanism for plant adaptation to the environment through the miR156‐SPLs‐DFR pathway, which coordinates development and abiotic stress tolerance.