不同小麦品种根区微生物特征及对土壤氮素水平的响应

Characteristics of root-associated microbiomes and their responses to soil nitrogen levels in different wheat cultivars

  • 摘要: 植物根区微生物在植物养分吸收以及生长发育过程中发挥重要作用。为研究不同小麦品种根区微生物群落结构差异, 本研究选择‘科农9204’ ‘科农2011’ ‘京411’和‘百农207’ 4个小麦品种, 于高氮300 kg(N)·hm−2和低氮0 kg(N)·hm−2条件下进行田间试验, 在分蘖期、拔节期和灌浆期采集根区样品。通过16S rRNA基因高通量测序技术比较分析不同小麦品种根际土壤和根内生细菌群落结构和多样性, 同时测定小麦植株的生理参数。结果表明, ‘科农9204’在3个生育期及不同氮素水平下相对其他3个品种均具有较高的地上部氮素吸收量(除分蘖期低氮条件)。小麦根际土壤和根内生细菌群落的优势菌门均为变形菌门(Proteobacteria)和放线菌门(Actinobacteria)。相比其他3个品种, ‘科农 9204’ 的根际土壤细菌群落在拔节期低氮水平下富集了根瘤菌目(Rhizobiales)和芽单胞菌属(Gemmatimonas), 在灌浆期高氮水平下富集了弗兰克氏菌目(Frankiales)。相关性分析表明, 根际土壤细菌群落中的节杆菌属(Arthrobacter)、链霉菌属(Streptomyces)、红色杆菌属(Rubrobacter)和类诺卡氏菌属(Nocardioides)与小麦地上部生物量和地上部氮素吸收量呈显著正相关, 马赛菌属(Massilia)、砂单胞菌属(Arenimonas)、假单胞菌属(Pseudomonas)和黄杆菌属(Flavobacterium)与小麦地上部全氮含量呈显著正相关。上述结果表明, 小麦可能通过调控根区微生物群落来影响养分吸收, 且这种影响具有品种特异性。本研究为明确小麦与微生物互作机制、发掘对小麦有益的微生物并应用到农业生产中提供了依据。

     

    Abstract: Plant root-associated microorganisms play important roles in nutrient uptake and plant growth. In order to illustrate the differences in the root-associated microbial community structure of different wheat cultivars, four wheat cultivars (i.e., ‘Kenong 9204’ ‘Kenong 2011’ ‘Jing 411’ and ‘Bainong 207’) were planted under 0 kg(N)·hm−2 (low nitrogen level) and 300 kg(N)·hm−2 (high nitrogen level), and the rhizosphere and root samples were collected at the tillering, jointing, and filling stages. The bacterial diversity and community structure in the rhizosphere and root endosphere of different wheat cultivars were analyzed using 16S rRNA high-throughput sequencing, and the physiological parameters of wheat were determined. Compared with the other three cultivars, ‘Ke-nong 9204’ had higher aboveground nitrogen accumulation at the three growth stages and under two nitrogen levels, except at the tillering stage with a low nitrogen level. Proteobacteria and Actinobacteria were the dominant bacteria in the wheat rhizosphere and root endosphere. Compared to the other three cultivars, ‘Kenong 9204’ enriched Rhizobiales and Gemmatimonas in the rhizosphere soil bacterial community under low nitrogen level at the jointing stage and enriched Frankiales under high nitrogen level at the filling stage. Correlation analysis showed that Arthrobacter, Streptomyces, Rubrobacter, and Nocardioides in the rhizosphere soil bacterial communities were significantly positively correlated with aboveground biomass and nitrogen accumulation; Massilia, Arenimonas, Pseudomonas, and Flavobacterium were significantly positively correlated with aboveground nitrogen content. Our results indicate that wheat may affect nutrient uptake by regulating the composition of the microbial community in the root zone and that this effect is cultivar-specific. This study provides useful information for understanding plant-microbe interactions in wheat and harnessing beneficial microbes for agricultural production.

     

/

返回文章
返回