As the second most abundant natural polymer,accounting for approximately 30％of the organic carbon in the biosphere,lignin plays an essential role in plant development.However,a high lignin content affects the nutritional quality of alfalfa(Medicago sativa L),the most widely cultivated perennial legume forage crop.Histological analysis indicated that G-lignin and S-lignin were present in the stem,leaf,and petiole of alfalfa,and the deposition of lignin increased gradually in descending internodes.Neutral detergent fiber(NDF),acid detergent fiber(ADF),and acid detergent lignin(ADL)contents continually increased from the top to the bottom of the stem,and ADL content showed a similar trend in leaves.Alfalfa leaves and stems from five different nodes(1,2,4,6,and 8)were used as materials to investigate molecular reg-ulatory mechanisms in lignin synthesis by RNA sequencing.Respectively 8074 and 7752 differentially expressed genes(DEGs)were identified in leaves and stems,and 1694 DEGs were common to the two tissues."Phenylpropanoid biosynthesis"was the most enriched pathway in both leaves and stems,and 134 key regulatory genes in lignin synthesis were identified by a weighted gene co-expression network analysis.The NAC family transcription factor MsNST1 gene was highly expressed in old leaf and stem tis-sues.The deposition pattern of G-and S-lignin differed among M.truncatula wild-type,nst1 mutants,and overexpression lines,and the transcription levels of lignin synthesis genes such as HCT,F5H,and COMT in these three materials also differed.These results suggest that MsNST1 affects lignin synthesis in alfalfa.These findings provide a genetic basis and abundant gene resources for further study of the molecular mechanisms of lignin synthesis,laying a foundation for low-lignin alfalfa breeding research.

Qiang Zhou;Pei Mao;Dong Luo;Xutian Chai;Hao Deng;Qiangen Fang;Longfa Fang;Zhibiao Nan;Jiangqi Wen;Zhipeng Liu

State Key Laboratory of Grassland Agro-ecosystems,Key Laboratory of Grassland Livestock Industry Innovation,Ministry of Agriculture and Rural Affairs,Engineering Research Center of Grassland Industry,Ministry of Education,College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,Gansu,China;Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011,Xinjiang,China;College of Grassland Science/Key Laboratory of Grassland Ecosystem of the Ministry of Education,Gansu Agricultural University,Lanzhou 730020,Gansu,China;Noble Research Institute,LLC,Ardmore,OK 73401,USA

作物学报（英文版）

[1]Qiang Zhou;Pei Mao;Dong Luo;Xutian Chai;Hao Deng;Qiangen Fang;Longfa Fang;Zhibiao Nan;Jiangqi Wen;Zhipeng Liu-.Comparative transcriptome analyses reveal that the MsNST1 gene affects lignin synthesis in alfalfa(Medicago sativa L.))[J].作物学报（英文版）,2022(04):1059-1072

MsNST1,Respectively,Phenylpropanoid,nst1,F5H

Comparative,transcriptome,analyses,reveal,that,affects,lignin,alfalfa,Medicago,sativa,second,most,abundant,natural,polymer,accounting,approximately,organic,carbon,biosphere,plays,essential,role,plant,development,However,nutritional,quality,widely,cultivated,perennial,legume,forage,crop,Histological,analysis,indicated,were,present,leaf,petiole,deposition,increased,gradually,descending,internodes,Neutral,detergent,fiber,NDF,acid,ADF,ADL,contents,continually,from,top,bottom,showed,similar,trend,leaves,Alfalfa,stems,five,used,materials,investigate,molecular,mechanisms,by,sequencing,differentially,expressed,genes,DEGs,identified,common,tissues,biosynthesis,was,enriched,pathway,both,key,regulatory,weighted,network,NAC,family,transcription,highly,old,pattern,differed,among,truncatula,wild,type,mutants,overexpression,lines,levels,such,HCT,COMT,these,three,also,These,results,suggest,findings,provide,genetic,basis,resources,further,study,laying,foundation,low,breeding,research

0.484499