To understand the growth response to drought, we performed a proteomics study in the leaf growth zone of maize (Zea mays L.) seedlings and functionally characterized the role of starch biosynthesis in the regulation of growth, photosynthesis and antioxidant capacity, using the shrunken‐2 mutant (sh2), defective in ADP‐glucose pyrophosphorylase. Drought altered the abundance of 284 proteins overrepresented for photosynthesis, amino acid, sugar and starch metabolism, and redox‐regulation. Changes in protein levels correlated with enzyme activities (increased ATP synthase, cysteine synthase, starch synthase, RuBisCo, peroxiredoxin, glutaredoxin, thioredoxin and decreased triosephosphate isomerase, ferredoxin, cellulose synthase activities, respectively) and metabolite concentrations (increased ATP, cysteine, glycine, serine, starch, proline and decreased cellulose levels). The sh2 mutant showed a reduced increase of starch levels under drought conditions, leading to soluble sugar starvation at the end of the night and correlating with an inhibition of leaf growth rates. Increased RuBisCo activity and pigment concentrations observed in WT, in response to drought, were lacking in the mutant, which suffered more oxidative damage and recovered more slowly after re‐watering. These results demonstrate that starch biosynthesis contributes to maintaining leaf growth under drought stress and facilitates enhanced carbon acquisition upon recovery.

中文翻译：

---

在干旱胁迫下，玉米的淀粉生物合成有助于维持光合作用和叶片生长。

要了解生长应对干旱，我们在玉米叶片生长区（进行蛋白质组学研究玉米L.）幼苗和功能特点淀粉合成的生长，光合作用和抗氧化能力的调节作用，使用shrunken- 2突变体（sh2），ADP-葡萄糖焦磷酸化酶有缺陷。干旱改变了284种蛋白质的丰度，这些蛋白质在光合作用，氨基酸，糖和淀粉的代谢以及氧化还原调节方面被大量代表。蛋白质水平的变化与酶活性（ATP合酶，半胱氨酸合酶，淀粉合酶，RuBisCo，过氧化物酶，谷氨酰胺，硫氧还蛋白和三磷酸磷酸异构酶，铁氧还蛋白，纤维素合酶活性分别降低）和代谢物浓度（ATP，半胱氨酸，糖分升高）相关。丝氨酸，淀粉，脯氨酸和纤维素含量降低）。该SH2突变体显示出在干旱条件下淀粉水平降低的增加，导致在夜晚结束时可溶性糖饥饿，并且与叶片生长速率的抑制有关。突变体缺乏在WT中观察到的增加的RuBisCo活性和色素浓度，以应对干旱，突变体遭受更多的氧化损伤，并且在重新浇水后恢复较慢。这些结果表明，淀粉的生物合成有助于在干旱胁迫下维持叶片的生长，并促进恢复后碳的吸收。