Division of Crop Production, ICAR-National Rice Research Institute, Cuttack, Odisha, India.
J Basic Microbiol. 2019 Oct;59(10):963-978. doi: 10.1002/jobm.201900275. Epub 2019 Aug 14.
The diversity of cellulolytic bacteria from the rice-pulse system can be sourced for identification of efficient cellulose decomposing microbial strains. In the present study, the abundance, structural diversity, and cellulolytic potential of the culturable bacterial community were studied in 5-year old rice-pulse system under different resource conservation technologies. Higher cellulose (68% more) and xylanase (35% more) activities were observed under zero tilled soil. The populations of cellulolytic bacteria were significantly higher (44%) in zero tillage (ZT) treatment than those of conventional practice. Results revealed that the cellulolytic bacterial diversity was found to be significantly higher under ZT practice, but the present population may not be sufficient for effective recycling of organic wastes in this system. Out of 290 bacterial isolates, 20 isolates had significantly higher cellulolytic activities, of which the top three superior isolates were received from ZT practice. The cellulolytic bacterial diversity based on 16S rDNA sequencing data revealed that the Firmicutes was the most dominant phyla and the Bacillus spp. were the common genus, the observation also showed that there were 17 different haplotypes were recorded among 20 isolates of cellulolytic bacteria. The present findings indicated that long-term ZT in the rice-pulse system could be a unique source for efficient cellulose decomposing bacteria and further the efficient bacterial strains isolated from this system can be used as efficient bioinoculants for in situ as well as ex-situ decomposition of rice straw particularly in conservation agriculture.
从稻豆系统中分离的纤维素分解细菌的多样性可用于鉴定高效纤维素分解微生物菌株。本研究在不同资源保护技术下,研究了 5 年生稻豆系统中可培养细菌群落的丰度、结构多样性和纤维素分解潜能。免耕土壤中纤维素(增加 68%)和木聚糖酶(增加 35%)活性更高。在免耕(ZT)处理中,纤维素分解细菌的数量明显更高(增加 44%),比传统耕作的数量更高。结果表明,ZT 实践下纤维素分解细菌的多样性明显更高,但目前的种群数量可能不足以有效回收该系统中的有机废物。在 290 个细菌分离物中,有 20 个分离物具有明显更高的纤维素分解活性,其中前三个优势分离物来自 ZT 实践。基于 16S rDNA 测序数据的纤维素分解细菌多样性表明,厚壁菌门是最占优势的门,芽孢杆菌属是常见的属,观察还表明,在 20 个纤维素分解细菌分离物中记录了 17 个不同的单倍型。本研究结果表明,长期在稻豆系统中进行免耕可能是高效纤维素分解细菌的独特来源,此外,从该系统中分离出的高效细菌菌株可作为原位和异位分解水稻秸秆的有效生物接种剂,特别是在保护性农业中。