Effects of silencing TT8 and HB12 on in vitro nutrients degradation and VFA production in relation to molecular structures of alfalfa (Medicago sativa)

Abstract

BACKGROUND Transparent Testa8 (TT8) and Homeobox12 (HB12) are two transcriptional factors in plant phenylpropanoid pathways and were reported to be positively related to lignin content. Alfalfa with silenced TT8 (TT8i) and HB12 (HB12i) was therefore generated using the RNA interference (RNAi) technique. Although lignin was found to be high in HB12i, such gene‐silencing of alfalfa resulted in nutrient profiles that might be suitable for grazing. To extend the nutritional evaluation of transformed alfalfa, ground samples of 11 HB12i, 5 TT8i and 4 wild type (WT) were incubated in rumen fluid : buffer solution for 0, 2, 4, 8, 12, 24 and 48 h at 39 °C. Dry matter (DM) and neutral detergent fiber (NDF) degradations at each time point, and production of volatile fatty acids (VFA) at 4, 12, 24 and 48 h were analyzed, as well as degradation and production kinetics. The correlations and regressions between nutritive profiles and attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectral parameters were determined. RESULTS Both transformed genotypes had lower DM degradation and HB12i had lower VFA production compared with WT. Structural carbohydrate (STC) parameters were found to be negatively correlated with DM degradation and VFA production. The kinetics of DM degradation and VFA production were predicted from spectral parameters with good estimation power. CONCLUSION Silencing of HB12 and TT8 affected fermentation characteristics of alfalfa and some fermentation characteristics were predictable from spectral parameters using ATR‐FTIR spectroscopy. © 2019 Society of Chemical Industry

Overexpression of miR156 and Silencing SPL6RNAi and SPL13RNAi Genes in Medicago sativa on the Changes of Carbohydrate Physiochemical, Fermentation, and Nutritional Profiles

“…This VFA production pattern of alfalfa is consistent with previous studies. 13,14 The C 2 /C 3 ratio was about 2.2, which is slightly lower than alfalfa hay in previous studies. 13,28 This might be attributed to the differences in chemical compositions and experiment variations.…”

“…Moreover, total carbohydrate (CHO) and non-fiber carbohydrate (NFC) were also calculated according to Higgs et al 12 Ruminal degradation of each fraction was estimated with its empirical degradation rate (K d ), which was obtained from the feed library of NDS Professional (RUM&N, Reggio Emilia, Italy), and passage rate (K p ) of 4.5%. 13,14 2.4. Truly Digestive Nutrients and Energy Value.…”

“…DM degradations of alfalfa in this study were higher compared to alfalfa samples in previous studies. 13,14,21,32 This is because alfalfa samples in this study were harvested at early the vegetative stage and lower NDF compared to those in previous studies. In contrast, Wang et al 33 reported similar in vitro DM degradation of Lc-transformed alfalfa, which accumulates anthocyanins in leaves and stems and had similar NDF and protein contents as samples in this study.…”

“…Furthermore, genetic modifications also had no effect on NDF degradation, which is similar to the findings of a previous study. 14 This suggests that genetic modification might only affect the NDF content but had no influence on degradability of NDF.…”

Using attenuated‐total‐reflection Fourier‐transformed spectroscopy to reveal molecular structural differences among willow (Salix spp.) foliage cultivars in relation to their potential as fodders

“…ATR‐FTIR combined with multivariate statistical analysis, has been successfully applied to the differentiation and classification of Citrus species 13 and almond varieties 14 . More recently, this technique has been used to detect changes in the molecular structure of alfalfa induced by genetic modifications, 7,15 which can efficiently predict the ruminal fermentation kinetics 16 . Therefore, the application of ATR‐FTIR to willow foliage samples might be useful to obtain an in‐depth knowledge of the differential molecular profile of the plant parts and cultivars, thus combining the benefits of bioenergy production and animal nutrition for developing efficient agroforestry systems.…”