Sahu Pramod K, Singh Shailendra, Singh Udai B, Chakdar Hillol, Sharma Pawan K, Sarma Birinchi K, Teli Basavaraj, Bajpai Raina, Bhowmik Arpan, Singh Harsh V, Saxena Anil K
ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, India.
Department of Mycology and Plant Pathology, Institute of Agricultural Science, Banaras Hindu University, Varanasi, India.
Front Microbiol. 2021 Oct 18;12:744733. doi: 10.3389/fmicb.2021.744733. eCollection 2021.
Endophytic bacilli of ethano-botanical plant were screened for salt stress-alleviating traits in tomato. Four promising endophytes ( BTL5, GTR8, GTR11, and GTS16) were used in this study. Confocal scanning laser microscopic studies revealed the inter-genera colonization of endophytes in tomato plants, giving insights for widening the applicability of potential endophytes to other crops. Furthermore, in a pot trial under 150 mM NaCl concentration, the inoculated endophytes contributed in reducing salt toxicity and improving recovery from salt-induced oxidative stress by different mechanisms. Reduction in reactive oxygen species (ROS) (sub-cellular HO and superoxide) accumulation was observed besides lowering programmed cell death and increasing chlorophyll content. Endophyte inoculation supplemented the plant antioxidant enzyme system the modulation of enzymatic antioxidants, , peroxidase, ascorbate peroxidase, superoxide dismutase, and catalase, apart from increasing proline and total phenolics. Antioxidants like proline have dual roles of antioxidants and osmoregulation, which might also have contributed to improved water relation under elevated salinity. Root architecture, ., root length, projection area, surface area, average diameter, tips, forks, crossings, and the number of links, was improved upon inoculation, indicating healthy root growth and enhanced nutrient flow and water homeostasis. Regulation of Na/K balance and water homeostasis in the plants were also evident from the modulation in the expression of abiotic stress-responsive genes, ., 1, 1, 1, 2, 16, and 39. Shoot tissues staining with light-excitable Na indicator Sodium Green Tetra (tetramethylammonium) salt showed low sodium transport and accumulation in endophyte-inoculated plants. All four endophytes exhibited different mechanisms for stress alleviation and indicated complementary effects on plant growth. Furthermore, this could be harnessed in the form of a consortium for salt stress alleviation. The present study established inter-genera colonization of endophytes in tomato and revealed its potential in maintaining Na/K balance, reducing ROS, and improving root architecture under elevated salinity.
对乙醇植物内生芽孢杆菌进行筛选，以研究其在番茄中缓解盐胁迫的特性。本研究使用了四种有前景的内生菌（BTL5、GTR8、GTR11和GTS16）。共聚焦扫描激光显微镜研究揭示了内生菌在番茄植株中的属间定殖，为扩大潜在内生菌在其他作物上的应用提供了思路。此外，在150 mM NaCl浓度的盆栽试验中，接种的内生菌通过不同机制有助于降低盐毒性并改善盐诱导的氧化应激恢复。除了降低程序性细胞死亡和增加叶绿素含量外，还观察到活性氧（ROS）（亚细胞HO和超氧化物）积累减少。内生菌接种补充了植物抗氧化酶系统，除了增加脯氨酸和总酚含量外，还调节了酶促抗氧化剂，如过氧化物酶、抗坏血酸过氧化物酶、超氧化物歧化酶和过氧化氢酶。脯氨酸等抗氧化剂具有抗氧化和渗透调节的双重作用，这也可能有助于在盐度升高的情况下改善水分关系。接种后根系结构，如根长、投影面积、表面积、平均直径、根尖、根叉、交叉点和连接数得到改善，表明根系生长健康，养分流动和水分稳态增强。植物中Na/K平衡和水分稳态的调节也从非生物胁迫响应基因，如1、1、1、2、16和39的表达调节中明显看出。用光激发的Na指示剂四甲基铵盐对地上部组织染色显示，接种内生菌的植株中钠的运输和积累较低。所有四种内生菌都表现出不同的胁迫缓解机制，并对植物生长显示出互补效应。此外，这可以以联合体的形式用于缓解盐胁迫。本研究确定了内生菌在番茄中的属间定殖，并揭示了其在盐度升高时维持Na/K平衡、减少ROS和改善根系结构方面的潜力。
