Abstract Background and Aims The stomatal conductance (gs) of most plant species decreases in response to elevated atmospheric CO2 concentration. This response could have a significant impact on plant water use in a future climate. However, the regulation of the CO2-induced stomatal closure response is not fully understood. Moreover, the potential genetic links between short-term (within minutes to hours) and long-term (within weeks to months) responses of gs to increased atmospheric CO2 have not been explored. Methods We used Arabidopsis thaliana recombinant inbred lines originating from accessions Col-0 (strong CO2 response) and C24 (weak CO2 response) to study short- and long-term controls of gs. Quantitative trait locus (QTL) mapping was used to identify loci controlling short- and long-term gs responses to elevated CO2, as well as other stomata-related traits. Key Results Short- and long-term stomatal responses to elevated CO2 were significantly correlated. Both short- and long-term responses were associated with a QTL at the end of chromosome 2. The location of this QTL was confirmed using near-isogenic lines and it was fine-mapped to a 410-kb region. The QTL did not correspond to any known gene involved in stomatal closure and had no effect on the responsiveness to abscisic acid. Additionally, we identified numerous other loci associated with stomatal regulation. Conclusions We identified and confirmed the effect of a strong QTL corresponding to a yet unknown regulator of stomatal closure in response to elevated CO2 concentration. The correlation between short- and long-term stomatal CO2 responses and the genetic link between these traits highlight the importance of understanding guard cell CO2 signalling to predict and manipulate plant water use in a world with increasing atmospheric CO2 concentration. This study demonstrates the power of using natural variation to unravel the genetic regulation of complex traits.

中文翻译：

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拟南芥短期和长期气孔二氧化碳反应的遗传控制


摘要 背景和目的 大多数植物物种的气孔导度（gs）随着大气二氧化碳浓度的升高而降低。这种反应可能会对未来气候下的植物用水产生重大影响。然而，二氧化碳诱导的气孔关闭反应的调节尚不完全清楚。此外，尚未探索gs对大气二氧化碳增加的短期（几分钟到几小时内）和长期（几周到几个月内）反应之间的潜在遗传联系。方法 我们使用源自种质 Col-0（强 CO2 响应）和 C24（弱 CO2 响应）的拟南芥重组自交系来研究 gs 的短期和长期对照。数量性状基因座 (QTL) 作图用于识别控制对二氧化碳升高的短期和长期 gs 反应以及其他气孔相关性状的基因座。主要结果 短期和长期气孔对二氧化碳浓度升高的反应显着相关。短期和长期反应均与 2 号染色体末端的 QTL 相关。该 QTL 的位置使用近等基因系进行了确认，并精细定位到 410 kb 区域。该QTL不对应于任何涉及气孔关闭的已知基因，并且对脱落酸的反应性没有影响。此外，我们还发现了许多与气孔调节相关的其他位点。结论 我们鉴定并证实了一个强 QTL 的作用，该 QTL 对应于一个未知的气孔关闭调节因子，响应 CO2 浓度升高。 短期和长期气孔二氧化碳反应之间的相关性以及这些性状之间的遗传联系凸显了了解保卫细胞二氧化碳信号传导以预测和操纵大气二氧化碳浓度不断增加的世界中植物用水的重要性。这项研究证明了利用自然变异来揭示复杂性状的遗传调控的力量。