Improved forage quality and biomass yield of alfalfa (Medicago sativa L.) by Arabidopsis QQS orphan gene
Improved forage quality and biomass yield of alfalfa (Medicago sativa L.) by Arabidopsis QQS orphan gene
复制标题
DOI：
10.1016/j.cpb.2023.100295
复制
发表时间：
2023-09-20
影响因子：
5.4
通讯作者：
Zhang, Wanjun
中科院分区：
文献类型：
--
作者：
Wang, Kexin;Yan, Jianing;Zhang, Wanjun
提高苜蓿的粗饲料含量和消化率是苜蓿品质育种的关键。拟南芥（Arabidopsis thaliana）的孤儿基因QQS（Quine Starch）已被证明在不同的粮食作物中提高蛋白质含量并改变碳水化合物组成。但苜蓿与其它粮食作物在农艺性状和营养条件上存在显著差异。为探讨QQS在苜蓿中的生物学功能及其分子机制，本研究构建了QQS转基因植株及其分离群体（T1代），并对其在正常和缺氮条件下的表现进行了评价。结果表明，在低氮条件下，QQS能显著提高苜蓿的全氮和粗蛋白含量，并增加根瘤重量。此外，QQS转基因品系还显示出中性洗涤纤维（NDF）和木质素水平降低，提高了饲料消化率。通过RNA测序和RT-qPCR分析，发现QQS影响了苜蓿碳氮代谢、木质素合成和氨基酸合成与降解途径相关基因的表达。此外，QQS还通过增加苜蓿的分支数和株高提高了苜蓿的生物产量。研究结果表明，QQS作为一种有效的分子工具，可以提高苜蓿生物产量和整体品质，对苜蓿育种业满足优质高产牧草的持续需求具有重要意义。
Improving the forage quality of alfalfa in terms of digestibility and crude content is essential for any alfalfa quality breeding programs. Arabidopsis thaliana orphan gene QQS (Qua-Quine Starch) has been shown to improve protein content and alter carbohydrate composition in different food crops. However, there are significant differences in agronomic traits and nutritional conditions between alfalfa and other food crops. To explore the biological function and molecular mechanisms of QQS in alfalfa, we generated QQS transgenic plants and their segregated population (T1 generation), and evaluated their performance under normal-and nitrogen-deficient conditions. Our findings indicate that QQS can significantly enhance the total nitrogen and crude protein content of alfalfa and increase nodule weight under low-nitrogen conditions. Furthermore, QQS transgenic lines also showed reduced levels of neutral detergent fiber (NDF) and lignin, improving forage digestibility. By RNA sequencing and RT-qPCR analysis, we found that QQS affected the expression of genes involved in carbon and nitrogen metabolism, lignin biosynthesis and amino acid biosynthesis and degradation pathways in alfalfa. In addition, QQS also improved alfalfa biomass yield by increasing branch number and plant height in both greenhouse and field conditions. Our results demonstrate that QQS as a useful molecular tool can improve alfalfa biomass yield and overall forage quality and could have significant implications for the alfalfa breeding industry in satisfying the constant demands for high-quality and high-yielding forage.