PDF(Pubmed)
Abstract：
Drought presents a significant abiotic stress that threatens crop productivity worldwide. Rhizosphere bacteria play pivotal roles in modulating plant growth and resilience to environmental stresses. Despite this, the extent to which rhizosphere bacteria are instrumental in plant responses to drought, and whether distinct cassava (Manihot esculenta Crantz) varieties harbor specific rhizosphere bacterial assemblages, remains unclear. In this study, we measured the growth and physiological characteristics, as well as the physical and chemical properties of the rhizosphere soil of drought-tolerant (SC124) and drought-sensitive (SC8) cassava varieties under conditions of both well-watered and drought stress. Employing 16S rDNA high-throughput sequencing, we analyzed the composition and dynamics of the rhizosphere bacterial community. Under drought stress, biomass, plant height, stem diameter, quantum efficiency of photosystem II (Fv/Fm), and soluble sugar of cassava decreased for both SC8 and SC124. The two varieties\' rhizosphere bacterial communities\' overall taxonomic structure was highly similar, but there were slight differences in relative abundance. SC124 mainly relied on Gamma-proteobacteria and Acidobacteriae in response to drought stress, and the abundance of this class was positively correlated with soil acid phosphatase. SC8 mainly relied on Actinobacteria in response to drought stress, and the abundance of this class was positively correlated with soil urease and soil saccharase. Overall, this study confirmed the key role of drought-induced rhizosphere bacteria in improving the adaptation of cassava to drought stress and clarified that this process is significantly related to variety.
摘要：
干旱是一种严重的非生物胁迫，威胁着全世界的作物生产力。根际细菌在调节植物生长和对环境胁迫的恢复力中起关键作用。尽管如此,根际细菌在植物对干旱的反应中发挥作用的程度，以及不同的木薯（ManihotesculentaCrantz）品种是否具有特定的根际细菌组合，尚不清楚。在这项研究中,我们测量了生长和生理特征，以及在水分充足和干旱胁迫条件下，耐旱（SC124）和干旱敏感（SC8）木薯品种的根际土壤的物理和化学性质。采用16SrDNA高通量测序，我们分析了根际细菌群落的组成和动态。在干旱胁迫下，生物量，植物高度,阀杆直径,光系统II的量子效率(Fv/Fm)，SC8和SC124的木薯可溶性糖均降低。这两个品种的根际细菌群落总体分类结构高度相似，但相对丰度略有不同。SC124主要依靠γ-变形杆菌和酸性杆菌来应对干旱胁迫，该类的丰度与土壤酸性磷酸酶呈正相关。SC8主要依靠放线菌响应干旱胁迫,该类别的丰度与土壤脲酶和土壤糖酶呈正相关。总的来说,这项研究证实了干旱诱导的根际细菌在提高木薯对干旱胁迫的适应性中的关键作用，并阐明了这一过程与品种显着相关。
