Starch biosynthesis contributes to the maintenance of photosynthesis and leaf growth under drought stress in maize

• DOI: 10.1111/pce.13813
• Publication Date: 2020-06-03T08:56:39Z
• Authors: Hamada AbdElgawad; Viktoriya Avramova; Geert Baggerman; Geert Van Raemdonck; Dirk Valkenborg; Xaveer Van Ostade; Yves Guisez; Els Prinsen; Han Asard; Wim Van den Ende; Gerrit T. S. Beem...
• Keywords: EXPRESSION; CARBOHYDRATE-METABOLISM; drought; maize; Zea mays; Antioxidants; CELL-CYCLE PROGRESSION; 03 medical and health sciences; proteomics; Gene Expression Regulation, Plant; EARLY SEEDLING DEVELOPMENT; OXIDATIVE STRESS; Amino Acids; Photosynthesis; Biology; Plant Proteins; 2. Zero hunger; 0303 health sciences; Science & Technology; photosynthesis; IDENTIFICATION; Dehydration; sh2mutant; starch; C-4; Plant Sciences; Starch; ABSCISIC-ACID; 15. Life on land; 6. Clean water; Droughts; Plant Leaves; PLANT-MITOCHONDRIA; leaf growth; Mutation; Plant Stomata; Life Sciences & Biomedicine; GLUCOSE PYROPHOSPHORYLASE; Cell Division

AbstractTo 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.