摘要
本试验旨在研究盐胁迫对苜蓿营养品质及附着微生物群落的影响。试验处理包括无盐胁迫(盐含量<1‰,作为对照)、轻度盐胁迫(盐含量1‰~2‰)、中度盐胁迫(盐含量2‰~3‰)和重度盐胁迫(盐含量3‰~4‰)。每个盐胁迫试验处理设置3个小区,每个小区面积为30 m2(5 m×6 m)。结果表明:中度盐胁迫下苜蓿酸性洗涤纤维和中性洗涤纤维含量显著低于其他处理(P<0.05)。中度盐胁迫下苜蓿谷氨酸、脯氨酸、可溶性蛋白质、粗蛋白质和可溶性碳水化合物含量与其他处理相比显著增加(P<0.05)。所有处理的Shannon指数和Chao1指数均无显著差异(P>0.05)。主坐标分析(PCoA)显示盐胁迫未完全改变苜蓿表面附着微生物群落的结构。所有处理下苜蓿门水平附着核心菌群为变形菌门(84.48%~92.91%)、放线菌门(4.30%~6.47%)、拟杆菌门(0.39%~10.59%)和厚壁菌门(0.61%~3.02%),属水平附着核心菌群为泛菌属(47.17%~56.11%)、假单胞菌属(10.58%~19.88%)、鞘脂单胞菌属(5.69%~9.32%)、甲基杆菌属(1.75%~7.87%)、根瘤菌属(0.48%~4.92%)和肠杆菌属(0.43%~4.05%)。随着盐胁迫的增强,甲基杆菌属和根瘤菌属的相对丰度降低,中度盐胁迫和重度盐胁迫处理显著低于无盐胁迫处理(P<0.05)。基于KEGG的微生物群落功能预测表明,微生物功能主要集中在碳水化合物代谢、氨基酸代谢、能量代谢和核酸代谢上,其中碳水化合物代谢是主要的代谢方式。相关性分析表明,根瘤菌属的相对丰度与酸性洗涤纤维、木质素和中性洗涤纤维含量呈显著正相关关系(P<0.001,P<0.01,P<0.05),与粗蛋白质、谷氨酸、脯氨酸和可溶性碳水化合物含量呈显著负相关关系(P<0.01);甲基杆菌属的相对丰度与酸性洗涤纤维和木质素含量呈显著正相关关系(P<0.01,P<0.05),与谷氨酸含量呈显著负相关关系(P<0.01);盐胁迫与鞘脂单胞菌属的相对丰度呈显著正相关关系(P<0.05),与甲基杆菌属的相对丰度呈显著负相关关系(P<0.05)。综上可知,中度盐胁迫(盐含量2‰~3‰)能够提高苜蓿营养品质,改善附着的微生物群落中拟杆菌门和厚壁菌门的相对丰度。
The present study aimed to investigate the effects of salt stress on nutritional quality and attached microbial community of alfalfa. The experimental treatments included no salt stress(salt content<1‰,as control),mild salt stress(salt content 1‰ to 2‰),moderate salt stress(salt content 2‰ to 3‰)and severe salt stress(salt content 3‰ to 4‰). Three plots were set up for each salt stress treatment,and the area of each plot was 30 m2(5 m×6 m). The results showed that the acid detergent fiber and neutral detergent fiber contents of alfalfa under moderate salt stress were significantly lower than those of alfalfa under other treatments(P <0.05),and mild salt stress could significantly increase the contents of glutamic acid,proline,soluble protein,crude protein and soluble carbohydrate of alfalfa compared with other treatments(P < 0. 05). No significant differences were observed on Shannon index and Chao1 index among treatments(P > 0. 05). The results of principal coordinate analysis(PCoA)showed that salt stress did not completely change the microbial community structure attached to the surface of alfalfa. Under all treatments,the phylum-core-microbiome were Proteobacteria(84.48% to 92.91%),Actinobacteria(4.30% to 6.47%),Bacteroidetes(0.39% to 10.59%)and Firmicutes(0. 61% to 3. 02%),and the genus-predominant-microbiome were Pantoea(47. 17% to56.11%),Pseudomonas(10. 58% to 19. 88%),Sphingomonas(5. 69% to 9. 32%),Methylobacterium(1.75% to 7.87%),Rhizobium(0.48% to 4.92%)and Enterobacter(0.43% to 4.05%). With the increase of salt stress,the relative abundances of Methylobacterium and Rhizobium decreased,which under moderate salt stress and severe salt stress were significantly lower than no salt stress(P<0.05). Prediction of microbial community functions based on KEGG showed that microbial functions were mainly concentrated in carbohydrate metabolism,amino acid metabolism,energy metabolism and nucleic acid metabolism,of which carbohydrate metabolism was the main metabolic mode. Correlation analysis showed that the relative abundance of Rhizobium was significantly positively correlated with acid detergent fiber,lignin and neutral detergent fiber content(P<0.001,P<0.01,P<0.05),and there was a significant negative correlation between Rhizobium relative abundance and crude protein,glutamate,proline and soluble carbohydrate contents(P<0.01);the relative abundance of Methylobacterium was significantly positively correlated with acid detergent fiber and lignin content(P<0.01,P<0.05),and there was a significant negative correlation between Methylobacterium relative abundance and glutamate content(P<0.01);there was a significant positive correlation between salt stress and Sphingomonas relative abundance(P<0.05),and a significant negative correlation with Methylobacterium relative abundance(P<0.01). In conclusion,moderate salt stress(salt content 2‰ to 3‰)can improve the nutritional quality and the relative abundances of Bacteroidetes and Firmicutes in attached microbial community of alfalfa.[Chinese Journal of Animal Nutrition,2023,35(1):439-449]
作者
常春
卢强
孙林
都帅
格根图
尹强
贾玉山
CHANG Chun;LU Qiang;SUN Lin;DU Shuai;GE Gentu;YIN Qiang;JIA Yushan(College of Grassland,Resources and Environment,Inner Mongolia Agricultural University,Hohhot 010010,China;Institute of Grassland Research,Chinese Academy of Agriculture Sciences,Hohhot 010010,China;Inner Mongolia Academy of Agricultural&Animal Husbandry Sciences,Hohhot 010010,China;College of Animal Science,Zhejiang University,Hangzhou 310058,China)
出处
《动物营养学报》
CAS
CSCD
北大核心
2023年第1期439-449,共11页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
国家重点研发计划(2017YFD0502103-3)
国家牧草产业技术体系鄂尔多斯综合试验站(CARS-34)
中央级公益性科研院所基本科研业务费专项资金(1610332020016)
内蒙河套地区盐碱地苜蓿加工调制技术集成与产业化示范项目(201802069)
草产品加工利用关键技术研发与产业化示范创新人才团队。
关键词
盐胁迫
苜蓿
营养品质
微生物群落
salt stress
alfalfa
nutritional quality
microbial community
