植物根际促生菌的筛选、定殖分析及对玉米生长的影响

Screening and Colonization Analysis of Rhizosphere Bacteria and Effects on Maize Growth

为促进植物促生菌剂的开发与应用,分离玉米根系促生菌株,并以玉米促生细菌(壳聚糖酶产生菌YM0137)为研究对象,阐明菌株YM0137在玉米根系的定殖,并测定菌株YM0137对玉米产量的影响。通过局部梯度溶液稀释技术分离纯化菌株;玉米植株接种细菌采用灌根接种法,筛选检测显著促进玉米生长与发育的菌种;利用16S rRNA基因序列的解析以及生理生化反应,判断菌种YM0137的生物学分类地位;通过菌落测定法并结合扫描电镜,确定菌株YM0137在玉米根表的定殖量;采用酶标仪检测离体条件下菌株YM0137的生长曲线;采用碱裂解法提取细菌质粒;并将菌肥YM0137施用于田间进行实收测产。筛选出对玉米促生效果显著的菌株YM0137,与对照相比,菌株YM0137处理的玉米幼苗株高增加了18.5%;经系统发育与生理生化分析,菌株YM0137为壳聚糖酶产生菌(Mitsuaria sp.);菌株YM0137可通过产生的微菌落定殖在玉米根表上,且在玉米根表的定殖量呈现逐渐上升的趋势;同时研究发现菌株YM0137存在内生质粒;测产结果表明菌肥YM0137替代25%化肥与常规施肥在玉米产量上没有显著差异,但与不施化肥相比,能显著提高玉米产量,可减少化肥施用。

In order to promote the development and application of plant growth promoting rhizobacteria, promoting rhizobacteria of maize was isolated, and the bacteria of maize(Mitsuaria sp. YM0137) was based on the colonization of strain YM0137 in maize roots. The effect of strain YM0137 on maize yield was determined. The strains were purified by local gradient solution dilution technique, select bacteria to promote maize growth, determine the classification status of strain YM0137 by 16S rRNA gene sequence analysis and physiological and biochemical reaction, determine the colonization of strain YM0137 by colony measurement and SEM, detect the growth curve of strain YM0137, and apply the fertilizer YM0137 in the field. For strain YM0137, compared with the control, the plant height of maize seedlings treated with strain YM0137 was increased by 18.5%;After the phylogenetic and physiological and biochemical analysis, strain YM0137 was a chitosanase-producing bacterium(Mitsuaria sp.);Strain YM0137 could colonize on the maize root surface by the produced microcolonies, and the colonization quantity in the maize root surface showed a gradually increasing trend;At the same time, an endogenous plasmid was found in the strain YM0137;The yield test results showed that there was no significant difference between bacterial fertilizer YM0137 replacing 25% chemical fertilizer and conventional fertilizer in maize yield, but compared with no chemical fertilizer, it could significantly increase maize yield, reduce chemical fertilizer application.