背景:种类繁多的微生物,包括细菌,生活在植物的根际区,对植物发育有有利和不利的影响。有益的结果是由于存在促进植物生长(PGPR)的根际细菌。
结果:在这项研究中,从羽扇豆根际分离出一种细菌菌株,并在遗传上鉴定为粘质沙雷氏菌(OK482790)。在体外和体内证实了几种生物化学和遗传特征,以确定OK482790菌株是PGPR的能力。体外结果表明产生不同的裂解酶(蛋白酶,脂肪酶,纤维素酶,和过氧化氢酶),抗菌化合物(氰化氢,和铁载体),氨,亚硝酸盐,和硝酸盐及其将硝酸盐还原为亚硝酸盐的能力。在计算机和体外筛选中提出了OK482790菌株可能的反硝化-DNRA-硝化途径。基因组筛选表明存在编码Nar膜结合传感器蛋白的亚硝酸盐和硝酸盐基因(NarK,NarQ和NarX)。硝酸盐和亚硝酸盐还原酶编码基因(NARI,NarJ,NarH,NarG和NapC/NirT)和(NirB,NirC,除了硝基还原酶(NTR)和几种氧化还原酶之外,还发现了NirD)。在小麦幼苗上的体内结果证实,通过土壤接种OK482790菌株,幼苗的生长得到了显着改善。
结论:这项研究提供了证据,证明了粘质沙菌OK482790通过反硝化-DNRA-硝化途径参与氮循环,并证明了其能够产生多种酶和化合物的能力,这些酶和化合物支持植物-微生物相互作用的有益作用,以维持植物的生长和发育,从而实现更安全的环境。
A wide variety of microorganisms, including bacteria, live in the rhizosphere zone of plants and have an impact on plant development both favorably and adversely. The beneficial outcome is due to the presence of rhizobacteria that promote plant growth (PGPR).
In this study, a bacterial strain was isolated from lupin rhizosphere and identified genetically as Serratia marcescens (OK482790). Several biochemically and genetically characteristics were confirmed in vitro and in vivo to determine the OK482790 strain ability to be PGPR. The in vitro results revealed production of different lytic enzymes (protease, lipase, cellulase, and catalase), antimicrobial compounds (hydrogen cyanide, and siderophores), ammonia, nitrite, and nitrate and its ability to reduce nitrate to nitrite. In silico and in vitro screening proposed possible denitrification-DNRA-nitrification pathway for OK482790 strain. The genome screening indicated the presence of nitrite and nitrate genes encoding Nar membrane bound sensor proteins (NarK, NarQ and NarX). Nitrate and nitrite reductase encoding genes (NarI, NarJ, NarH, NarG and NapC/NirT) and (NirB, NirC, and NirD) are also found in addition to nitroreductases (NTR) and several oxidoreductases. In vivo results on wheat seedlings confirmed that seedlings growth was significantly improved by soil inoculation of OK482790 strain.
This study provides evidence for participation of S. marcescens OK482790 in nitrogen cycling via the denitrification-DNRA-nitrification pathway and for its ability to produce several enzymes and compounds that support the beneficial role of plant-microbe interactions to sustain plant growth and development for a safer environment.