Location: Adaptive Cropping Systems LaboratoryTitle: The potential role of sucrose-transport gene expression in the photosynthetic and yield response of rice cultivars to future CO2 concentration
|ZHANG, JISHUANG - Chinese Academy Of Sciences|
|LI, DANFENG - Chinese Academy Of Sciences|
|XI, XU - Chinese Academy Of Sciences|
|ZHU, JIANGUO - Chinese Academy Of Sciences|
|LIU, GANG - Chinese Academy Of Sciences|
|ZHU, CHUNWU - Chinese Academy Of Sciences|
Submitted to: Physiologia Plantarum
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2019
Publication Date: N/A
Interpretive Summary: Carbon dioxide (CO2), along with sunlight, water and nutrients constitutes one of the four resources needed for plants to grow. As such, the sudden increase in its concentration in the atmosphere (up 30% since 1960, with a projected 50% increase by the end of the century) could be exploited to boost crop yields. However, it is also evident that different varieties of rice respond differently in terms of rising CO2, some yielding more, others less. Why is this? To determine, in part, the basis for variation among rice cultivars, and international team of plant breeders, ecologists and physiologists from the U.S. and China examined contrasting rice lines to future CO2 levels. It was found that lines which had a strong yield response to rising CO2, had increased activity of sucrose-transport genes (OsSUT1 and OsSUT2), which aided the transfer of sucrose (additional carbon as sugars) to growing seed; conversely, those which had less response had less gene activity. While a broader array of rice lines needs to be examined, these initial results suggest that expression of sucrose transport may be a key characteristic for converting additional atmospheric CO2 into seed yield for rice, an important global cereal. These data should be of value to agronomists, plant breeders, and those interested in food security.
Technical Abstract: The metabolic basis for observed differences in the yield response of rice to projected carbon dioxide concentration, [CO2], is unclear. In this study, three rice cultivars, differing in their yield response to elevated [CO2]; were grown at ambient and elevated [CO2] using Free-Air CO2 Enrichment (FACE) technology. Flag leaves were used to determine: (a) if manipulative increases in sink strength decreased soluble sucrose concentration for the “weak” responders; and, (b) whether the genetic expression of OsSUT1 and OsSUT2 was associated with accumulation of soluble sugars and maintenance of photosynthetic capacity. For the weak responders, photosynthetic capacity declined under elevated [CO2], and was associated with accumulation of soluble sugars. For these cultivars, increasing sink relative to source strength did not increase photosynthesis; and no change in OsSUT1 or OsSUT2 expression was observed. In contrast, the “strong” responder did not show an increase in soluble sugars or a decline in photosynthesis; but did show significant increases in OsSUT1 and OsSUT2 expression at elevated [CO2]. Overall, these data suggest that expression of sucrose transport (i.e. OsSUT1 and OsSUT2) may be associated with maintenance of photosynthetic capacity of the flag leaf during grain fill, and, potentially, greater yield response of rice as atmospheric [CO2] increases.