稻虾共生模式对水稻结实期根系分泌物及微生物的影响

Effects of rice-crayfish integrated model on root exudates and microorganisms of rice during grain filling

摘要:

为了探明稻虾共生模式中虾对水稻生长的促进作用，实验以红螯螯虾为养殖对象，比较了稻虾共生和水稻单作2种模式下结实期水稻根系分泌物 (有机酸、氨基酸和酚酸)和微生物群落结构的差异。结果显示，稻虾共生模式显著增加了结实期水稻根系苹果酸、酒石酸、马来酸、异亮氨酸、丝氨酸以及总有机酸和总氨基酸的分泌量，分别较对照组提高了29.07%、61.84%、10.8%、136.11%、218.54%、21.50%和12.69%；对羟基苯甲酸、香豆酸及酚酸总量降低了20.38%、25.5%和9.48%。在结实后期，稻虾共生模式在门水平上显著增加了Methylomirabilota和Latescibacterota的丰度，分别提高了101.11%和48.86%；在属的水平上，稻虾共生模式显著提高了Vicinamibacterales-norank和Latescibacterota-norank的丰度，分别较对照组提高了22.96%和48.23%。相关性分析表明，根系分泌的有机酸和酚酸总量皆与绿弯菌门 (Chloroflexi)和放线菌门 (Actinobacteriota)呈显著负相关，酒石酸、异亮氨酸、丝氨酸及总有机酸与放线菌门也呈显著负相关，酒石酸和丝氨酸与Vicinamibacterales-norank呈显著正相关。研究表明，稻虾共生模式可以显著提高水稻根系有机酸和氨基酸的分泌量，为Methylomirabilota、Latescibacterota、Latescibacterota-norank和Vicinamibacterales-norank微生物提供碳源，促使其在水稻根际聚集，加速土壤有效养分的释放，进而提高水稻根系对养分的吸收速率，促进水稻的高产。

Abstract:

The traditional rice-crayfish coculture systems may develop a novel sustainable agriculture by clarifying whether crayfish is serving as a stimulus for rice growth. In order to investigate this mechanism, the experiment selected Cherax quadricarinatus as the cultured species and compared rice root exudates (organic acids, amino acids and phenolic acids) and microbial community structure in integrated rice-crayfish farming (RSC)and rice monoculture (RMC). Gas chromatography/mass spectrometry (GC–MS) and Illumina MiSeq sequencers were adopted as the research method. The results showed that the secretions of malic acid, tartaric acid, maleic acid, isoleucine, serine, total organic acids and total amino acids in rice roots were increased significantly in coculture system during the grain filling stage, with the gap reaching 29.07% ,61.84%,10.8%, 136.11%, 218.54%, 21.50% and 12.69% respectively compared to the control group; The total amount of p-hydroxybenzoic acid, coumaric acid and phenolic acid decreased by 20.38%, 25.5% and 9.48%. In the hard dough stage, the abundance of Methylomirabilota and Latescibacterota were increased in integrated farming system by 101.11% and 48.86%, respectively; At the genus level, the rice-crayfish integrated model significantly increased the abundance of Vicinamibacteria-norank and Latescibacterota-norank by 22.96% and 48.23%. Correlation analysis showed that the total amount of organic acids and phenolic acids secreted by roots were negatively correlated with Chloroflexi and Actinobacteriota. Similarly，tartaric acid, isoleucine, serine and total organic acids were negatively correlated with Actinobacteriota. In contrast, tartaric acid and serine were positively correlated with Vicinabacteria-norank. In conclusion integrated rice-crayfish farming could significantly enhance the secretion of organic acids and amino acids in rice roots and tap sufficient carbon source for the microorganisms of Methylomirabilota, Latescibacterota, Latescibacterota-norank and Vicinamibacteria-norank, thus to stimulate their accumulation in rice rhizosphere and accelerate the release of soil nutrients. These findings provide unique insights into how positive interactions between crayfish and rice root properties in terms of efficient nutrient absorption and how modern agricultural systems might be improved by boosting grain yield and quality.