Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Sci Total Environ. 2024 Oct 15;947:174778. doi: 10.1016/j.scitotenv.2024.174778. Epub 2024 Jul 14.
Salt stress can limit crop productivity, and there are differences in salt tolerance among plant varieties; however, we lack a comprehensive understanding of how keystone species obtained from different plant varieties under salt stress change plant biomass by driving root exudate secretion and regulating the Na:K ratio. We conducted a pot experiment for three wheat varieties (JiMai32 (JM32), XiaoYan60 (XY60), and ShanRong3 (SR3)) under saline/nonsaline soil conditions. Salt stress tended to significantly reduce wheat biomass, and the biomass reduction rates of the different varieties decreased in the order JM32 < XY60 < SR3. The compositions of the bacterial and fungal communities in the root endosphere, rhizosphere and bulk soil were measured, and salt-induced microbial taxa were isolated to identify keystone species from the co-occurrence networks and to study their effects on physiological responses to salinity in wheat varieties. We observed that root exudates participated in the regulation of the Na:K ratio, thereby affecting wheat biomass, and this process was regulated by keystone species. JM32 was enriched in microorganisms that promote plant growth and resistance to salt stress, such as Burkholderiales, Sordariomycetes, Alteromonadaceae, Acremonium, and Dokdonella, and inhibited microorganisms that are sensitive to the environment (salt, nutrients) and plant pathogens, such as Nocardioidaceae, Nitrospira, Cytophagaceae, Syntrophobacteriaceae, and Striaticonidium. XY60 inhibited microorganisms with biological control and disease inhibition potential, such as Agromyces and Kaistobacter. SR3-enriched pathogens, such as Aurantimonadaceae and Pseudogymnoascus, as well as microorganisms with antagonistic pathogen potential and the ability to treat bacterial infections, such as RB41 and Saccharothrix, were inhibited. Our results confirmed the crucial function of salt-induced keystone species in enhancing plant adaptation to salt stress by driving root exudate secretion and regulating the Na:K ratio, with implications for exploring reasonable measures to improve plant salt tolerance.
盐胁迫会限制作物的生产力，不同植物品种对盐的耐受性存在差异；然而，我们对不同植物品种的关键种在盐胁迫下如何通过驱动根分泌物的分泌和调节钠钾比来改变植物生物量知之甚少。我们在盐/非盐土壤条件下进行了三种小麦品种（冀麦 32（JM32）、小偃 60（XY60）和山融 3（SR3））的盆栽实验。盐胁迫往往会显著降低小麦生物量，不同品种的生物量减少率按 JM32<XY60<SR3 的顺序递减。测量了根内圈、根际和体土中细菌和真菌群落的组成，并从共现网络中分离出盐诱导的微生物分类群，以鉴定关键种，并研究它们对小麦品种盐胁迫生理响应的影响。我们观察到，根分泌物参与了钠钾比的调节，从而影响小麦生物量，而这一过程受到关键种的调节。JM32 富集了促进植物生长和耐盐的微生物，如伯克霍尔德氏菌、Sordariomycetes、交替单胞菌科、Acremonium 和 Dokdonella，并抑制了对环境（盐、养分）和植物病原体敏感的微生物，如诺卡氏菌科、硝化螺旋菌科、噬纤维菌科、互营杆菌科和Striaticonidium。XY60 抑制了具有生物防治和抑菌潜力的微生物，如 Agromyces 和 Kaistobacter。SR3 富集了病原体，如 Aurantimonadaceae 和 Pseudogymnoascus，以及具有拮抗病原体潜力和治疗细菌感染能力的微生物，如 RB41 和 Saccharothrix。我们的结果证实了盐诱导的关键种通过驱动根分泌物的分泌和调节钠钾比来增强植物对盐胁迫的适应的关键作用，这对探索提高植物耐盐性的合理措施具有重要意义。
