Wang Bo, Wang Xicheng, Wang Zhuangwei, Zhu Kefeng, Wu Weimin
Institute of Pomology, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing City, Jiangsu Province, China.
Department of Technology Commercialization, Jiangsu Academy of Agricultural Sciences, Nanjing City, Jiangsu Province, China.
Front Microbiol. 2023 Feb 20;14:1102547. doi: 10.3389/fmicb.2023.1102547. eCollection 2023.
Soil salinization is a serious abiotic stress for grapevines. The rhizosphere microbiota of plants can help counter the negative effects caused by salt stress, but the distinction between rhizosphere microbes of salt-tolerant and salt-sensitive varieties remains unclear.
This study employed metagenomic sequencing to explore the rhizosphere microbial community of grapevine rootstocks 101-14 (salt tolerant) and 5BB (salt sensitive) with or without salt stress.
Compared to the control (treated with ddHO), salt stress induced greater changes in the rhizosphere microbiota of 101-14 than in that of 5BB. The relative abundances of more plant growth-promoting bacteria, including Planctomycetes, Bacteroidetes, Verrucomicrobia, Cyanobacteria, Gemmatimonadetes, Chloroflexi, and Firmicutes, were increased in 101-14 under salt stress, whereas only the relative abundances of four phyla (Actinobacteria, Gemmatimonadetes, Chloroflexi, and Cyanobacteria) were increased in 5BB under salt stress while those of three phyla (Acidobacteria, Verrucomicrobia, and Firmicutes) were depleted. The differentially enriched functions (KEGG level 2) in 101-14 were mainly associated with pathways related to cell motility; folding, sorting, and degradation functions; glycan biosynthesis and metabolism; xenobiotics biodegradation and metabolism; and metabolism of cofactors and vitamins, whereas only the translation function was differentially enriched in 5BB. Under salt stress, the rhizosphere microbiota functions of 101-14 and 5BB differed greatly, especially pathways related to metabolism. Further analysis revealed that pathways associated with sulfur and glutathione metabolism as well as bacterial chemotaxis were uniquely enriched in 101-14 under salt stress and therefore might play vital roles in the mitigation of salt stress on grapevines. In addition, the abundance of various sulfur cycle-related genes, including genes involved in assimilatory sulfate reduction (, , , and ), sulfur reduction (), SOX systems (), sulfur oxidation (), organic sulfur transformation (, , , and ), increased significantly in 101-14 after treatment with NaCl; these genes might mitigate the harmful effects of salt on grapevine. In short, the study findings indicate that both the composition and functions of the rhizosphere microbial community contribute to the enhanced tolerance of some grapevines to salt stress.
土壤盐渍化是葡萄藤面临的一种严重非生物胁迫。植物的根际微生物群有助于对抗盐胁迫造成的负面影响，但耐盐和盐敏感品种的根际微生物之间的差异仍不明确。
本研究采用宏基因组测序技术，探究了在有或无盐胁迫条件下，葡萄砧木101-14（耐盐）和5BB（盐敏感）的根际微生物群落。
与对照（用双蒸水处理）相比，盐胁迫对101-14根际微生物群的诱导变化大于5BB。在盐胁迫下，101-14中更多促进植物生长的细菌的相对丰度增加，包括浮霉菌门、拟杆菌门、疣微菌门、蓝细菌门、芽单胞菌门、绿弯菌门和厚壁菌门，而在盐胁迫下，5BB中只有四个门（放线菌门、芽单胞菌门、绿弯菌门和蓝细菌门）的相对丰度增加，而三个门（酸杆菌门、疣微菌门和厚壁菌门）的相对丰度减少。101-14中差异富集的功能（KEGG二级水平）主要与细胞运动、折叠、分选和降解功能、聚糖生物合成和代谢、异生物质生物降解和代谢以及辅因子和维生素代谢相关的途径有关，而在5BB中只有翻译功能差异富集。在盐胁迫下，101-14和5BB的根际微生物群功能差异很大，尤其是与代谢相关的途径。进一步分析表明，与硫和谷胱甘肽代谢以及细菌趋化性相关的途径在盐胁迫下在101-14中独特富集，因此可能在减轻葡萄的盐胁迫中发挥重要作用。此外，在NaCl处理后，101-14中各种与硫循环相关的基因的丰度显著增加，包括参与同化硫酸盐还原（、、、和）、硫还原（）、SOX系统（）、硫氧化（）、有机硫转化（、、、和）的基因；这些基因可能减轻盐对葡萄的有害影响。简而言之，研究结果表明，根际微生物群落的组成和功能都有助于提高一些葡萄对盐胁迫的耐受性。
