School of Applied Biosciences, Kyungpook National University, Daegu 41566, Republic of Korea.
Institute of Agricultural Science and Technology, Kyungpook National University, Daegu 41566, Republic of Korea.
J Microbiol Biotechnol. 2020 Oct 28;30(10):1500-1509. doi: 10.4014/jmb.2006.06010.
Drought is a major abiotic factor and has drastically reduced crop yield globally, thus damaging the agricultural industry. Drought stress decreases crop productivity by negatively affecting crop morphological, physiological, and biochemical factors. The use of drought tolerant bacteria improves agricultural productivity by counteracting the negative effects of drought stress on crops. In this study, we isolated bacteria from the rhizosphere of broccoli field located in Daehaw-myeon, Republic of Korea. Sixty bacterial isolates were screened for their growth-promoting capacity, in vitro abscisic acid (ABA), and sugar production activities. Among these, bacterial isolates YNA59 was selected based on their plant growth-promoting bacteria traits, ABA, and sugar production activities. Isolate YNA59 highly tolerated oxidative stress, including hydrogen peroxide (HO) and produces superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities in the culture broth. YNA59 treatment on broccoli significantly enhanced plant growth attributes, chlorophyll content, and moisture content under drought stress conditions. Under drought stress, the endogenous levels of ABA, jasmonic acid (JA), and salicylic acid (SA) increased; however, inoculation of YNA59 markedly reduced ABA (877 ± 22 ng/g) and JA (169.36 ± 20.74 ng/g) content, while it enhanced SA levels (176.55 ± 9.58 ng/g). Antioxidant analysis showed that the bacterial isolate YNA59 inoculated into broccoli plants contained significantly higher levels of SOD, CAT, and APX, with a decrease in GPX levels. The bacterial isolate YNA59 was therefore identified as sp. YNA59. Our current findings suggest that newly isolated drought tolerant rhizospheric sp. YNA59 is a useful stress-evading rhizobacterium that improved droughtstress tolerance of broccoli and could be used as a bio-fertilizer under drought conditions.
干旱是一种主要的非生物因素，它极大地降低了全球的作物产量，从而破坏了农业产业。干旱胁迫通过对作物形态、生理和生化因素产生负面影响，从而降低作物生产力。使用耐旱细菌可以通过抵消干旱胁迫对作物的负面影响来提高农业生产力。在这项研究中，我们从位于韩国大川面的西兰花田间根际分离出细菌。从这些细菌中筛选出 60 株具有促生长能力、体外脱落酸（ABA）和糖产生活性的细菌。其中，根据其具有植物促生菌特性、ABA 和糖产生活性，选择了细菌分离株 YNA59。分离株 YNA59 高度耐受氧化应激，包括过氧化氢（HO），并在培养液中产生超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性。YNA59 处理西兰花可显著提高植物生长特性、叶绿素含量和干旱胁迫条件下的水分含量。在干旱胁迫下，ABA、茉莉酸（JA）和水杨酸（SA）的内源性水平增加；然而，接种 YNA59 显著降低了 ABA（877±22ng/g）和 JA（169.36±20.74ng/g）的含量，同时提高了 SA 的水平（176.55±9.58ng/g）。抗氧化分析表明，接种到西兰花植物中的细菌分离株 YNA59 含有显著更高水平的 SOD、CAT 和 APX，而 GPX 水平降低。因此，该细菌分离株 YNA59 被鉴定为 sp. YNA59。我们的研究结果表明，新分离的耐旱根际 sp. YNA59 是一种有用的避胁迫根际细菌，可提高西兰花的耐旱性，可在干旱条件下用作生物肥料。
