期刊
JOURNAL OF EXPERIMENTAL BOTANY
卷 72, 期 12, 页码 4419-4434出版社
OXFORD UNIV PRESS
DOI: 10.1093/jxb/erab132
关键词
CAM; gas exchange; hydrolytic pathway; phosphorolytic pathway; starch
资金
- Marie Curie Fellowship
- Research Fund KU Leuven
- Colciencias
- Biotechnology and Biological Sciences Research Council, UK [BB/F009313/1]
- U.S. Department of Energy (DOE) Office of Science, Genomic Science Program [DE-SC0008834]
- BBSRC [BB/F009313/1] Funding Source: UKRI
The findings suggest that phosphorolytic starch degradation is critical for efficient operation of the CAM cycle and optimizing water use efficiency. Disruption of this pathway can lead to reduced growth and limited response to changes in light periods.
In plants with Crassulacean acid metabolism (CAM), it has been proposed that the requirement for nocturnal provision of phosphoenolpyruvate as a substrate for CO2 uptake has resulted in a re-routing of chloroplastic starch degradation from the amylolytic route to the phosphorolytic route. To test this hypothesis, we generated and characterized four independent RNAi lines of the obligate CAM species Kalanchoe fedtschenkoi with a >10-fold reduction in transcript abundance of plastidic alpha-glucan phosphorylase (PHS1). The rPHS1 lines showed diminished nocturnal starch degradation, reduced dark CO2 uptake, a reduction in diel water use efficiency (WUE), and an overall reduction in growth. A re-routing of starch degradation via the hydrolytic/amylolytic pathway was indicated by hyperaccumulation of maltose in all rPHS1 lines. Further examination indicated that whilst operation of the core circadian clock was not compromised, plasticity in modulating net dark CO2 uptake in response to changing photoperiods was curtailed. The data show that phosphorolytic starch degradation is critical for efficient operation of the CAM cycle and for optimizing WUE. This finding has clear relevance for ongoing efforts to engineer CAM into non-CAM species as a means of boosting crop WUE for a warmer, drier future.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据