Ji Chao, Liu Zhaoyang, Hao Liping, Song Xin, Wang Changdong, Liu Yue, Li Huying, Li Chaohui, Gao Qixiong, Liu Xunli
College of Forestry, Shandong Agriculture University, Taian, China.
State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, Taian, China.
Front Plant Sci. 2020 Jul 17;11:1094. doi: 10.3389/fpls.2020.01094. eCollection 2020.
The present study investigated the physiological and biochemical characteristics of HG-1 isolated from saline-alkali soil. We further studied the effect of this strain on the salt tolerance of wheat and on the community structure of nitrogen-fixing bacteria in rhizosphere soil. We determined that the investigated strain had high nitrogen fixation activity and produced iron carriers, 1-aminocyclopropane-1-carboxylic acid deaminase, and plant hormones. The metabolites of this strain contained 2,3-butanediol, [R-(R*, R*)], 2-heptanone, and other growth-promoting and antibacterial substances. The strain was also highly salt-tolerant (10% NaCl). After the inoculation of wheat with the HG-1 strain, we recorded increases in root length, plant height, fresh weight, and dry weight of 19.15%, 18.83%, 16.67%, and 17.96%, respectively, compared with uninoculated plants ( < 0.05). Compared with the leaves of uninoculated plants, the proline concentration in the leaves of inoculated plants increased by 12.43% ( < 0.05), the malondialdehyde level decreased by 27.26% ( < 0.05), K increased by 20.69%, Ca increased by 57.53% and Na decreased by 31.43% (all <0.05). Furthermore, we detected that inoculation with the HG-1 strain did not affect the species composition of nitrogen-fixing bacteria in wheat rhizosphere soil at the phylum level. However, the average relative abundance of Proteobacteria was significantly increased, whereas the abundance of Verrucomiorobia was significantly decreased compared with uninoculated plants. At the genus level, we detected 32 genera in control samples and 27 genera in inoculated samples, and the species diversity and relative abundance of samples inoculated with the HG-1 strain decreased compared with uninoculated plants. Inoculated samples had lower abundances of , , and . Our study demonstrated that the inoculation of wheat with HG-1 could promote the growth of wheat under salt stress and increase salt stress tolerance. The results of this study investigating the interaction among soil, plants, and microorganisms supplement agricultural microbial databases and could provide a reference for the development of microbial-based saline soil improvement programs.
本研究调查了从盐碱土中分离出的HG-1的生理生化特性。我们进一步研究了该菌株对小麦耐盐性以及根际土壤中固氮菌群落结构的影响。我们确定所研究的菌株具有高固氮活性，并能产生铁载体、1-氨基环丙烷-1-羧酸脱氨酶和植物激素。该菌株的代谢产物包含2,3-丁二醇、[R-(R*,R*)]、2-庚酮以及其他促生长和抗菌物质。该菌株还具有高耐盐性（10%氯化钠）。用HG-1菌株接种小麦后，与未接种的植株相比，我们记录到根长、株高、鲜重和干重分别增加了19.15%、18.83%、16.67%和17.96%（P<0.05）。与未接种植株的叶片相比，接种植株叶片中的脯氨酸浓度增加了12.43%（P<0.05），丙二醛水平降低了27.26%（P<0.05），钾增加了20.69%，钙增加了57.53%，钠降低了31.43%（均P<0.05）。此外，我们检测到用HG-1菌株接种不会影响小麦根际土壤中门水平上固氮菌的物种组成。然而，与未接种的植株相比，变形菌门的平均相对丰度显著增加，而疣微菌门的丰度显著降低。在属水平上，我们在对照样品中检测到32个属，在接种样品中检测到27个属，与未接种的植株相比，用HG-1菌株接种的样品的物种多样性和相对丰度降低。接种样品中 、 和 的丰度较低。我们的研究表明，用HG-1接种小麦可以促进盐胁迫下小麦的生长并提高耐盐胁迫能力。本研究关于土壤、植物和微生物之间相互作用的结果补充了农业微生物数据库，并可为基于微生物的盐碱土改良方案的制定提供参考。
