Junjie Wang 1, *, Yan Zhao 1 , Ian Ray 2 , Mingzhou Song 3
1 College of Ecology and Environmental Science, Inner Mongolia Agricultural University, Hohhot, China
2 Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM, USA
3 Department of Computer Science, New Mexico State University, Las Cruces, NM, USA

Abstract:Tolerance of alfalfa (Medicago sativaL.) to animal grazing varies widely within the species. However, the molecular mechanisms influencing the grazing tolerant phenotype remain uncharacterized. The objective of this study was to identify genes and pathways that control grazing response in alfalfa. We analyzed whole-plantde novotranscriptomes from grazing tolerant and intolerant populations ofM. sativassp.falcatasubjected to grazing by sheep. Among the Gene Ontology terms which were identified as grazing responsive in the tolerant plants and differentially enriched between the tolerant and intolerant populations (both grazed), most were associated with the ribosome and translation-related activities, cell wall processes, and response to oxygen levels. Twenty-one grazing responsive pathways were identified that also exhibited differential expression between the tolerant and intolerant populations. These pathways were associated with secondary metabolite production, primary carbohydrate metabolic pathways, shikimate derivative dependent pathways, ribosomal subunit composition, hormone signaling, wound response, cell wall formation, and anti-oxidant defense. Sequence polymorphisms were detected among several differentially expressed homologous transcripts between the tolerant and intolerant populations. These differentially responsive genes and pathways constitute potential response mechanisms for grazing tolerance in alfalfa. They also provide potential targets for molecular breeding efforts to develop grazing-tolerant cultivars of alfalfa.

‍‍Published inScientific Reports. 2016, 6: 19438

Doi: 10.1038/srep19438