高通量植物生理表型平臺助力保護細胞PIF4和HY5控制蒸騰活動研究

瀏覽次數：1474　發布日期：2023-2-10　來源：本站　僅供參考，謝絕轉載，否則責任自負

熱點

保護細胞中PIF4的高表達減少了蒸騰作用。

保護細胞中HY5的表達增強了蒸騰作用。

保護細胞中HY5的表達升高可以逆轉HXK1保護細胞活性所造成的低蒸騰作用。

摘要

全植物蒸騰作用受植物水力和氣孔運動的控制，受內源和環境信號的調節，光在其中起主導作用。氣孔孔徑不斷調整以適應光照強度和質量的變化，一方面確保光合作用的最佳CO2攝入，另一方面確保水分損失最小。光照和蒸騰作用之間的聯系已經很好地確立，但關于保衛細胞如何感知這些信號來影響氣孔導度的遺傳知識仍然有限。在目前的研究中，我們評估了兩個中心光響應轉錄因子的作用；bZIP家族轉錄因子延伸的下胚軸5（HY5）和基本螺旋環螺旋（BHLH）轉錄因子植物色素相互作用因子4（PIF4）。我們發現，PIF4在保衛細胞（GCPIF4）中的過度表達降低了蒸騰作用，并可以抑制PIF4突變體的高蒸騰作用。此外，我們發現GCHY5可以逆轉由糖傳感器HEXOKINASE1（HXK1，GCHXK）的保護細胞過度表達引起的低蒸騰作用，這是一種已建立的低蒸騰基因型。最后，我們認為GCHXK逆轉GCHY5的低蒸騰作用需要其他組織中內源性HY5的自動激活。這些發現支持了氣孔中光響應轉錄因子HY5和PIF4對蒸騰作用的持續晝夜調節，從而最終決定了整個植物的水分利用效率。

Guard cell activity of PIF4 and HY5 control transpiration

Highlights

Elevated expression of PIF4 in guard cells reduces transpiration.

Elevated expression of HY5 in guard cells enhances transpiration.

Elevated expression of HY5 in guard cells can reverse the low transpiration imposed by guard cell activity of HXK1.

Abstract

Whole-plant transpiration, controlled by plant hydraulics and stomatal movement, is regulated by endogenous and environmental signals, with the light playing a dominant role. Stomatal pore size continuously adjusts to changes in light intensity and quality to ensure optimal CO2 intake for photosynthesis on the one hand, together with minimal water loss on the other. The link between light and transpiration is well established, but the genetic knowledge of how guard cells perceive those signals to affect stomatal conductance is still somewhat limited. In the current study, we evaluated the role of two central light-responsive transcription factors; a bZIP-family transcription factor ELONGATED HYPOCOTYL5 (HY5) and the basic helix-loop-helix (BHLH) transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4), in the regulation of steady-state transpiration. We show that overexpression of PIF4 exclusively in guard cells (GCPIF4) decreases transpiration, and can restrain the high transpiration of the pif4 mutant. Expression of HY5 specifically in guard cells (GCHY5) had the opposite effect of enhancing transpiration rates of WT- Arabidopsis and tobacco plants and of the hy5 mutant in Arabidopsis. In addition, we show that GCHY5 can reverse the low transpiration caused by guard cell overexpression of the sugar sensor HEXOKINASE1 (HXK1, GCHXK), an established low transpiring genotype. Finally, we suggest that the GCHY5 reversion of low transpiration by GCHXK requires the auto-activation of the endogenous HY5 in other tissues. These findings support the existence of an ongoing diurnal regulation of transpiration by the light-responsive transcription factors HY5 and PIF4 in the stomata, which ultimately determine the whole-plant water use efficiency.

Keywords:Guard cells Stomata Transpiration HY5 PIF4 Water use efficiency

Plantarray是一款基于稱重的高通量、多傳感器生理表型平臺以及植物逆境生物學研究通用平臺。該系統可持續、實時測量位于不同環境條件下、陣列中每個植株的土壤-植物-空氣（SPAC）中的即時水流動。直接測量根系和莖葉系統水平衡和生物量增加，計算植物生理參數以及植物對動態環境的反饋。系統以有效、易用、無損的方式針對植物對不同處理的反應、預測植物生長和生產力進行定量比較，廣泛應用于生物脅迫和非生物脅迫以及植物栽培加速育種研究等，脅迫研究涵蓋干旱脅迫、鹽脅迫、重金屬脅迫、熱、冷脅迫、光脅迫以及灌溉/養分、CO₂指示、植物健康等領域的研究。