Silencing TT8 and HB12 Decreased Protein Degradation and Digestion, Microbial Synthesis, and Metabolic Protein in Relation to Molecular Structures of Alfalfa (Medicago sativa)

Abstract

This study aimed to explore the effects of silencing HB12 and TT8 genes on protein utilization characteristics of alfalfa. Ground samples of 11 HB12-silenced (HB12i), 5 TT8-silenced (TT8i) and 4 wild type (WT) were incubated in a Daisy II incubator with N15 labeled ammonium sulfate for 0, 4, 8, 12, and 24 h. CP degradation and degradational kinetics, microbial nitrogen fractions, and protein metabolic profiles were determined. Moreover, relationships between protein profiles and FTIR spectral parameters were estimated. Results showed that transgenic alfalfa had lower CP degradation, microbial protein, and total available protein compared with WT, especially for HB12i. In addition, CP degradation and protein metabolic profiles were closely correlated with FTIR spectral parameters and thereby could be predicted from spectral parameters. In conclusion, silencing of HB12 and TT8 genes in alfalfa decreased protein degradational and metabolic profiles, which were predictable with FTIR spectral parameters.

Comparative Transcriptome and Anatomic Characteristics of Stems in Two Alfalfa Genotypes

“…The identification of these lignin synthesis genes will promote the development of low-lignin alfalfa cultivars. As reported, a low-lignin alfalfa cultivar, KK179, characterized by its down-regulation of CCoAOMT , has been approved in many countries [ 42 ]. Here, a total of 12 differentially expressed genes, including PAL , 4CL , HCT , CAD , COMT and POD , were identified in four developmental stages between the cultivars.…”

Effects of Transparent Testa8 (TT8) gene and Homeobox12 (HB12) gene silencing in alfalfa (Medicago sativa L.) on molecular structure spectral profile in relation to energy, degradation, and fermentation characteristics in ruminant systems

“…Alfalfa plant samples were obtained from the Agriculture and Agri-Food Canada-Saskatoon Research and Development Centre (Saskatoon, Canada). The detailed processes of alfalfa transformation, growth conditions and harvest information were previously described ( Li et al., 2015 , Lei et al., 2018a , 2018b , 2019 ). Briefly, to make RNAi constructs, cDNA was synthesized from total alfalfa RNA that was extracted from the fourth internode.…”

“…Transparent Testa ( TT8 ) and Homeobox 12 ( HB12 ) are two transcriptional factors in this pathway. Observation from Brassica napus showed a negative relationship between lignin content and gene expression of TT8 and HB12 ( Li et al., 2016a ; Lei et al., 2018a , 2018b , 2019 ). Therefore, we transformed alfalfa with TT8 and HB12 RNAi constructs to silence these 2 genes in alfalfa.…”

“…In our previous studies, we reported (1) how gene silencing affected chemical profiles and total in vitro gas production relating to molecular structures of alfalfa plants ( Lei et al., 2018b ) and (2) how gene silencing affected protein degradation and digestion, microbial protein synthesis, and metabolic protein in relation to molecular structures of alfalfa ( Lei et al., 2019 ). The specific objectives of this study were to determine the effect of gene modification through silencing of TT8 and HB12 genes in alfalfa on (1) lignin and phenolic content, (2) bioenergic value, (3) carbohydrate and protein rumen degradable and undegradable fraction supply, and (4) in vitro ammonia production in response to silencing of TT8 and HB12 genes in alfalfa.…”