Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China.
Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin 150040, China.
Int J Mol Sci. 2024 Oct 10;25(20):10870. doi: 10.3390/ijms252010870.
Soil salinization is currently one of the main abiotic stresses that restrict plant growth. Plant endophytic bacteria can alleviate abiotic stress. The aim of the current study was to isolate, characterize, and assess the plant growth-promoting and saline and alkaline stress-alleviating traits of () isolates from maize. One endophytic bacterial isolate, named , was selected from the roots of maize grown in saline-alkali soil. The genome sequence analysis of the bacteria with a length of 5.8 Mbp includes about 700 genes that promote growth and 16 antioxidant activity genes that alleviate saline and alkaline stress. can grow below 400 mM NaHCO on the LB culture medium; The isolate displayed multiple plant growth-stimulating features, such as nitrogen fixation, produced indole-3-acetic acid (IAA), and siderophore production. This isolate had a positive effect on the resistance to salt of maize in addition to the growth. significantly promoted seed germination by enhancing seed vigor in maize whether under normal growth or NaHCO stress conditions. The seeds with NaHCO treatment exhibited higher reactive oxygen species (ROS) levels than the maize in inoculant on maize. can colonize the roots of maize. The inoculant plant increased chlorophyll in leaves, stimulated root and leaf growth, increased the number of lateral roots and root dry weight, increased the length and width of the blades, and dry weight of the blades. The application of inoculants can significantly reduce the content of malondialdehyde (MDA) and increase the activity of plant antioxidant enzymes (Catalase (CAT), Superoxide Dismutase (SOD), and Peroxidase (POD)), which may thereby improve maize resistance to saline and alkaline stress. Conclusion: isolate belongs to plant growth-promoting bacteria by having high nitrogen concentration, indoleacetic acid (IAA), and siderophore, and reducing the content of ROS through the antioxidant system to alleviate salt alkali stress. This study presents the potential application of as a biological inoculant to promote plant growth and mitigate the saline and alkaline effects of maize and other crops.
土壤盐渍化是目前限制植物生长的主要非生物胁迫因素之一。植物内生细菌可以缓解非生物胁迫。本研究旨在从玉米中分离、鉴定和评估具有促生长和耐盐碱性的内生细菌（）。从盐碱性土壤中生长的玉米根部分离到一株内生细菌，命名为。该细菌的基因组序列分析表明，其长度为 5.8 Mbp，包含约 700 个促进生长的基因和 16 个缓解盐碱性胁迫的抗氧化活性基因。在 LB 培养基上，该菌可以在低于 400mM NaHCO 的条件下生长；该分离株表现出多种促进植物生长的特性，如固氮、产生吲哚-3-乙酸（IAA）和产生铁载体。该分离株除了促进生长外，还对玉米的耐盐性有积极影响。在正常生长或 NaHCO 胁迫条件下，均能显著增强玉米种子活力，促进种子萌发。与对照相比，用 NaHCO 处理的种子表现出更高的活性氧（ROS）水平。该菌能定殖在玉米根中。接种植物的叶片叶绿素含量增加，刺激根和叶生长，增加侧根和根干重，增加叶片长度和宽度，叶片干重增加。接种剂的应用可显著降低丙二醛（MDA）含量，提高植物抗氧化酶（过氧化氢酶（CAT）、超氧化物歧化酶（SOD）和过氧化物酶（POD））活性，从而提高玉米耐盐碱性。结论：该分离株通过高氮浓度、吲哚乙酸（IAA）和铁载体促进植物生长，通过抗氧化系统降低 ROS 含量来缓解盐碱性胁迫，属于植物促生菌。本研究为将 作为生物接种剂应用于促进玉米和其他作物生长，减轻盐碱性影响提供了依据。
