摘要
干旱是草地植物面对的最大威胁,对耐旱草地植物的研究将促进人们更好地理解植物对干旱适应性反应背后的调控机制。牛枝子是优质的多年生强旱生牧草,分布于广袤的荒漠草原地区。目前对牛枝子抗旱研究主要集中在渗透调节物质变化、功能基因序列分析,但其抗旱性的内在机制尚不清楚。本研究采用单因素控水试验,土壤水分含量为田间持水量的70%~80%设为对照组(CK),田间持水量的20%~30%为严重干旱胁迫组(Tr),处理4周后,开展牛枝子生物量分配、水分利用、渗透调节、根系分布等生理生化指标测定,同时采集叶片和幼根进行转录组测序分析。结果表明,干旱胁迫条件下,牛枝子通过增加脯氨酸(Pro)、可溶性蛋白(SP)、可溶性糖(Ss)、K+等含量进行渗透调节来保持体内水分,增加同位素碳13(δ13C)和丙二醛(MDA)含量以提高水分利用效率和抗氧化能力,降低相对含水量(RWC)、胞间二氧化碳浓度(Ci)、气孔导度(Cond),减少生物量,增加根冠比等响应干旱胁迫。通过RNA-Seq差异基因表达分析,在叶中发现4058个差异基因,在根中发现2172个差异基因,叶和根中共有差异基因744个。这些差异基因(DEG)能够对干旱做出积极(上调)或消极(下调)的反应。叶中上调差异基因主要富集在植物-病原体相互作用、植物激素信号转导,而下调差异基因主要富集在光合代谢包括碳固定、光合作用天线蛋白合成、光合过程产物代谢。在根中上调差异基因主要富集在精氨酸与脯氨酸代谢、内质网中的蛋白质加工,下调差异基因主要富集在淀粉和蔗糖代谢、异黄酮生物合成、类黄酮生物合成。在牛枝子叶中差异表达的转录因子主要有AP2/ERF-ERF、NAC、bHLH、WRKY、C2H2,根中主要有HSF、MYB、AP2/ERF-ERF、WRKY。其中bHLH特异性下调表达,HSF特异性上调表达。根与叶中的吡咯啉-5-羧酸还原酶(P5CR)、脯氨酸亚氨肽酶(PL
Drought is the greatest threat to grassland plants,and research on drought-tolerant grassland plants will contribute to a better understanding of the regulatory mechanisms behind the adaptive responses of plants to drought.Lespedeza potaninii is a high quality,perennial,strongly drought tolerant forage species that is widely distributed in desert grassland areas in some parts of China.Current research on drought resistance in L.potaninii focuses on changes in osmoregulatory substances and functional gene sequence analysis,but the underlying mechanism of its drought resistance is still unclear.In this study,a single-factor water control experiment was conducted with soil moisture content of 70%-80% of the field water holding capacity for the control group(CK)and 20%-30% of the field water holding capacity for the severely drought stressed group(Tr).After 4 weeks of treatment,tests on physiological and biochemical indicators such as biomass distribution,water use,osmoregulation and root distribution were carried out on L.potaninii,while leaves and young roots were collected for transcriptome sequencing analysis.The results showed that under drought stress conditions,L.potaninii exhibited increased content of proline(Pro),a higher soluble protein content(SP),increased soluble sugar,increased K+ions for osmoregulation to maintain hydration of the plant tissues,increased δ13C indicating improved water use efficiency and increased malondialdehyde indicating oxidant stress,reduced relative water content,reduced leaf internal CO2 concentration and stomatal conductance,reduced biomass and increased root to crown ratio,among other changes,in response to drought stress.By RNA-Seq differential gene expression analysis,4058 differential genes were found in leaves and 2172 differential genes in roots,making a total of 744 differential genes in leaves and roots.These differential genes(DEGs)include those responding positively(up-regulated)or negatively(down-regulated)to drought.Up-regulated differentially expressed genes in le
作者
张浩
胡海英
李惠霞
贺海明
马霜
马风华
宋柯辰
ZHANG Hao;HU Hai-ying;LI Hui-xia;HE Hai-ming;MA Shuang;MA Feng-hua;SONG Ke-chen(College of Agriculture,Ningxia University,Yinchuan 750021,China)
出处
《草业学报》
CSCD
北大核心
2023年第7期188-205,共18页
Acta Prataculturae Sinica
基金
宁夏自然科学基金项目(2022AAC03080)
国家自然科学基金项目(32160406)
宁夏高等学校一流学科建设(草学学科)项目(NXY LXK2017A01)资助。
关键词
干旱胁迫
牛枝子
生理
转录组分析
drought stress
Lespedeza potaninii
physiological
transcriptome analysis
