Assessment of Stress Tolerance, Productivity, and Forage Quality in T1Transgenic Alfalfa Co-overexpressingZxNHXandZxVP1-1fromZygophyllum xanthoxylum.
Salinization, desertification, and soil nutrient deprivation are threatening the production of alfalfa (Medicago sativaL.) in northern China. We have previously generated T0transgenic alfalfa co-overexpressingZygophyllum xanthoxylum ZxNHXandZxVP1-1genes with enhanced salt and drought tolerance. To further develop this excellent breeding material into the new forage cultivar, stress tolerance, productivity, and forage quality of T1transgenic alfalfa (GM) were assessed in this study. The GM inherited the traits of salt and drought tolerance from T0generation. Most importantly, co-overexpression ofZxNHXandZxVP1-1enhanced the tolerance to Pi deficiency in GM, which was associated with more Pi accumulation in plants. Meanwhile, T1transgenic alfalfa developed a larger root system with increased root size, root dry weight and root/shoot ratio, which may be one important reason for the improvement of phosphorus nutrition and high biomass accumulation in GM under various conditions. GM also accumulated more crude protein, crude fiber, crude fat, and crude ash than wild-type (WT) plants, especially under stress conditions and in the field. More interestingly, the crude fat contents sharply dropped in WT (by 66-74%), whereas showed no change or decreased less in GM, when subjected to salinity, drought or low-Pi. Our results indicate that T1transgenic alfalfa co-overexpressingZxNHXandZxVP1-1shows stronger stress tolerance, higher productivity and better forage quality. This study provides a solid foundation for creating the alfalfa cultivars with high yield, good quality and wide adaptability on saline, dry, and nutrient-deprived marginal lands of northern China.
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University Lanzhou, China.
Peng
P
Kang
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University Lanzhou, China.
Ai-Ke
AK
Bao
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University Lanzhou, China.
Tanweer
T
Kumar
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University Lanzhou, China.
Ya-Qing
YQ
Pan
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University Lanzhou, China.
Zhulatai
Z
Bao
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University Lanzhou, China.
Fei
F
Wang
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University Lanzhou, China.
Suo-Min
SM
Wang
field trial; nutritive value; phosphorus deficiency; stress resistance; transgenic alfalfa