Genome-Wide Functional Analysis of Cotton (Gossypium hirsutum) in Response to Drought

Cotton is one of the most important crops for its natural textile fibers in the world. However, it often suffered from drought stress during its growth and development, resulting in a drastic reduction in cotton productivity. Therefore, study on molecular mechanism of cotton drought-tolerance is very important for increasing cotton production. To investigate molecular mechanism of cotton drought-resistance, we employed RNA-Seq technology to identify differentially expressed genes in the leaves of two different cultivars (drought-resistant cultivar J-13 and drought-sensitive cultivar Lu-6) of cotton. The results indicated that there are about 13.38% to 18.75% of all the unigenes differentially expressed in drought-resistant sample and drought-sensitive control, and the number of differentially expressed genes was increased along with prolonged drought treatment. DEG (differentially expression gene) analysis showed that the normal biophysical profiles of cotton (cultivar J-13) were affected by drought stress, and some cellular metabolic processes (including photosynthesis) were inhibited in cotton under drought conditions. Furthermore, the experimental data revealed that there were significant differences in expression levels of the genes related to abscisic acid signaling, ethylene signaling and jasmonic acid signaling pathways between drought-resistant cultivar J-13 and drought-sensitive cultivar Lu-6, implying that these signaling pathways may participate in cotton response and tolerance to drought stress.     

Identification of changes in Triticum aestivum L. leaf proteome in response to drought stress by 2D-PAGE and MALDI-TOF/TOF mass spectrometry

Drought is an abiotic stress that strongly influences plant growth, development and productivity. To gain a better understanding of the drought-stress responses at physiological and molecular level in wheat plants (Triticum aestivum cv. KTC86211), we performed a comparative physiological and proteomics analysis. Eight-day-old wheat seedlings were treated with polyethylene glycol-simulated drought stress for 0, 24, 48 and 72 h. Drought treatment resulted in alterations of morphology, increased relative electrolyte leakage and reduced length and weight on leaf and root. Stress-induced proteome changes were analyzed by two-dimensional gel electrophoresis in conjunction with MALDI-TOF/TOF. Twenty-three spots differed significantly between control and treated plants following 48 h of drought stress, with 19 upregulated, and 4 downregulated, in leaf tissues. All of the differentially expressed protein spots were identified, revealing that the majority of proteins altered by drought treatment were involved in reactive oxygen species scavenging enzymes and photosynthesis. Other proteins identified were involved in protein metabolism, cytoskeleton structure, defense response, acid metabolism and signal transduction. All proteins might contribute cooperatively to reestablish cellular homeostasis under drought stress. The present study not only provides new insights into the mechanisms of acclimation and tolerance to drought stress in wheat plants, but also provides clues for improving wheat’s drought tolerance through breeding or genetic engineering.     

基于RNA-Seq技术分析在金属矿上部生长的芒萁的差异表达基因

以生长于广西大厂锡多金属矿上部(重金属胁迫区)和未受矿化或污染影响的矿区外围(对照区)的芒萁〔Dicranopteris pedata(Houtt.)Nakaike〕为实验材料,对芒萁叶片进行转录组高通量测序,并对组装得到的unigenes经NCBI官方非冗余蛋白质序列数据库(Nr)、NCBI官方非冗余核苷酸序列数据库(Nt)、KEGG直系同源数据库(KO)、Swiss-Prot数据库(Swiss-Prot)、蛋白质家族数据库(Pfam)、基因功能分类体系数据库(GO)和真核生物直系同源序列数据库(KOG)进行注释,同时分析重金属胁迫区和对照区芒萁叶片间的差异表达unigenes.结果显示:测序获得19.56 Gb clean data,其中,重金属胁迫区和对照区芒萁叶片分别含10.14和9.42 Gb clean data.组装得到的250582个unigenes中有120097个unigenes得到注释,占unigenes总数的47.93%.与对照区相比较,重金属胁迫区芒萁叶片中上调和下调差异表达unigenes分别有208和620个,其中120个上调差异表达unigenes注释为代谢过程,占所有上调差异表达unigenes的57.69%;285个下调差异表达unigenes注释为催化活性,占所有下调差异表达unigenes的45.97%.重金属胁迫区芒萁叶片中15个unigenes与重金属转运和耐受相关,其中c44988 g1和c84121 g1的相对表达量分别极显著和显著高于对照区.研究结果显示:芒萁响应自然金属矿化或矿山重金属污染的基因可以用于生物地球化学找矿和土壤重金属污染检测.     

干旱胁迫条件下AMF促进小马鞍羊蹄甲幼苗生长的机理研究

采用温室水分控制试验,在干旱胁迫条件下,定量化研究优势丛枝菌根真菌(AMF)影响优势乡土植物小马鞍羊蹄甲(Bauhinia faberi var.microphylla)幼苗生长的机理,主要通过研究干旱胁迫条件下摩西球囊霉菌(Funneliformis mosseae)与小马鞍羊蹄甲的共生关系,阐明AMF在植物生长初期的作用。结果表明,干旱胁迫条件下,摩西球囊霉菌能够很好地侵染幼苗,侵染率高达89%—97%,并且不受水分条件影响。接种的幼苗最大光合速率、水分利用效率随着干旱胁迫程度从重度到轻度(水分从低到高)逐渐增大,相反地,叶片脯氨酸含量逐渐减小。接种显著地促进幼苗株高、叶片数、叶面积、根长、根面积等生长指标,提高幼苗各部分生物量、地上地下磷(P)含量。当含水量为60%田间持水量时,AMF促进小马鞍羊蹄甲幼苗吸收P的效果最好。接种还显著影响幼苗的生物量分配,在重度干旱胁迫时影响P分配,水分条件也显著影响幼苗的生物量分配。此外,接种和水分的交互作用对叶生物量、总生物量、生长指标以及地上部氮(N)总量影响显著。结果表明干旱胁迫条件下菌根效应显著,并在干旱条件下显著促进了小马鞍羊蹄甲幼苗的生长,这为进一步干旱河谷植被恢复提供了理论依据。     

紫鸭跖草根组织应答铜胁迫的转录组分析

紫鸭跖草是一种高耐铜的超积累植物,本研究首次应用RNA-Seq技术对其转录组进行分析。通过全长转录组分析组装了紫鸭跖草耐铜相关候选基因,通过转录组分析,共获得82 471条N50长度为2 299 bp的高质量unigene,为紫鸭跖草的进一步研究提供了丰富的数据。对照组(CK)、300 μmol/L胁迫组(CT1)和1 000 μmol/L胁迫组(CT2)的测序数据已保存在NCBI的SRA数据库中,登录号为SAMN11265427。CT1相比于CK,共有5 028条unigene在根组织中有显著性差异表达,约占全部unigene的6.10%,其中富集上调和下调的基因分别为3 138和1 890条;CT2相比于CT1,根中共有6 813个unigene富集差异表达,占所有unigene的8.26%。其中富集上调和下调的基因分别为2 555和4 258。随机选取10个基因进行qRT-PCR荧光定量分析,结果与Illumina测序数据一致,验证了基因数据差异表达的有效性。上述实验从分子水平上为研究铜胁迫下铜耐受的分子机制提供了理论依据。