Department of Energy Plant Research Laboratory, Michigan State University, East Lansing 48824, MI.
Plant Resilience Institute, Michigan State University, East Lansing 48824, MI.
Proc Natl Acad Sci U S A. 2023 Oct 10;120(41):e2309536120. doi: 10.1073/pnas.2309536120. Epub 2023 Oct 2.
Isoprene is emitted by some plants and is the most abundant biogenic hydrocarbon entering the atmosphere. Multiple studies have elucidated protective roles of isoprene against several environmental stresses, including high temperature, excessive ozone, and herbivory attack. However, isoprene emission adversely affects atmospheric chemistry by contributing to ozone production and aerosol formation. Thus, understanding the regulation of isoprene emission in response to varying environmental conditions, for example, elevated CO, is critical to comprehend how plants will respond to climate change. Isoprene emission decreases with increasing CO concentration; however, the underlying mechanism of this response is currently unknown. We demonstrated that high-CO-mediated suppression of isoprene emission is independent of photosynthesis and light intensity, but it is reduced with increasing temperature. Furthermore, we measured methylerythritol 4-phosphate (MEP) pathway metabolites in poplar leaves harvested at ambient and high CO to identify why isoprene emission is reduced under high CO. We found that hydroxymethylbutenyl diphosphate (HMBDP) was increased and dimethylallyl diphosphate (DMADP) decreased at high CO This implies that high CO impeded the conversion of HMBDP to DMADP, possibly through the inhibition of HMBDP reductase activity, resulting in reduced isoprene emission. We further demonstrated that although this phenomenon appears similar to abscisic acid (ABA)-dependent stomatal regulation, it is unrelated as ABA treatment did not alter the effect of elevated CO on the suppression of isoprene emission. Thus, this study provides a comprehensive understanding of the regulation of the MEP pathway and isoprene emission in the face of increasing CO.
异戊二烯由一些植物排放，是进入大气的最丰富的生物源碳氢化合物。多项研究阐明了异戊二烯对多种环境胁迫（包括高温、过量臭氧和草食性攻击）的保护作用。然而，异戊二烯的排放通过促进臭氧生成和气溶胶形成对大气化学产生不利影响。因此，了解异戊二烯排放对不同环境条件（例如，升高的 CO ）的调节，对于理解植物如何应对气候变化至关重要。随着 CO 浓度的升高，异戊二烯的排放会降低；然而，这种反应的潜在机制目前尚不清楚。我们证明，高 CO 介导的异戊二烯排放抑制与光合作用和光强无关，但随着温度的升高而降低。此外，我们在环境 CO 和高 CO 下收获的杨树叶片中测量了甲基赤藓醇 4-磷酸（MEP）途径代谢物，以确定为什么在高 CO 下异戊二烯的排放会减少。我们发现，高 CO 时羟甲基丁烯二磷酸（HMBDP）增加，二甲基烯丙基二磷酸（DMADP）减少。这意味着高 CO 阻碍了 HMBDP 向 DMADP 的转化，可能是通过抑制 HMBDP 还原酶活性，导致异戊二烯的排放减少。我们进一步证明，尽管这种现象类似于脱落酸（ABA）依赖性气孔调节，但它与 ABA 处理无关，因为 ABA 处理并没有改变升高的 CO 对异戊二烯排放抑制的影响。因此，本研究为面对不断增加的 CO，全面了解 MEP 途径和异戊二烯排放的调节提供了依据。
Zotero 插件
