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

Alfalfa ( L.) is a legume forage that is widely cultivated owing to its high biomass yield and favorable nutrient values. However, alfalfa contains relatively high lignin, which limits its utilization. Downregulation of two transcriptional factors, Transparent Testa8 () and Homeobox12 (), has been proposed to reduce lignin content in alfalfa. Therefore, silencing of (i) and i) in alfalfa was achieved by RNAi technology. The objective of this project was to determine effect of gene modification through silencing of and genes in alfalfa plants on lignin and phenolic content, bioenergic value, nutrient supply from rumen degradable and undegradable fractions, and in vitro ammonia production in response to the silencing of and genes in alfalfa. All gene silenced alfalfa plants (5 i and 11 i) were grown under greenhouse conditions with wild type as a control. Samples were analyzed for bioactive compounds, degradation fractions, truly digestible nutrients, energetic values and in vitro ammonia productions in ruminant systems. Furthermore, relationships between physiochemical, metabolic and fermentation characteristics and molecular spectral parameters were determined using vibrational molecular spectroscopy. Results showed that the i had higher lignin, while i had higher phenolics. Both silenced genotypes had higher rumen slowly degraded carbohydrate fractions and truly digestible neutral detergent fiber, but lower rumen degradable protein fractions. Moreover, the i had lower truly digestible crude protein, energetic values and ammonia production compared with other silenced genotypes. In addition, in relation to the nutritive values of alfalfa, structural carbohydrate parameters were negatively correlated, whereas alpha/beta ratio in protein structure was positively correlated. Furthermore, good predictions were obtained for degradation of protein and carbohydrate fractions and energy values from molecular spectral parameters. In conclusion, silencing of the and genes decreased protein availability and increased fiber availability. Silencing of the gene also increased lignin and decreased energy and rumen ammonia production. Moreover, nutritional alterations were closely correlated with molecular spectral parameters. Therefore, gene modification through silencing the and genes in alfalfa influenced physiochemical, metabolic and fermentation characteristics.