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The maize lilliputian1 (lil1) gene, encoding a brassinosteroid cytochrome P450 C-6 oxidase, is involved in plant growth and drought response

Author:
Castorina, Giulia, Persico, Martina, Zilio, Massimo, Sangiorgio, Stefano, Carabelli, Laura, Consonni, Gabriella
Source:
Annals of botany 2018 v.122 no.2 pp. 227-238
ISSN:
1095-8290
Subject:
Zea mays, alleles, biosynthesis, brassinosteroids, corn, cytochrome P-450, drought, epicuticular wax, epistasis, genetic analysis, gravitropism, leaves, mutants, mutation, oxygenases, plant adaptation, plant development, plant growth, plant hormones, pleiotropy, seedlings, transposons, water stress
Abstract:
Brassinosteroids (BRs) are plant hormones involved in many developmental processes as well as in plant–environment interactions. Their role was investigated in this study through the analysis of lilliputian1-1 (lil1-1), a dwarf mutant impaired in BR biosynthesis in maize (Zea mays). We isolated lil1-1 through transposon tagging in maize. The action of lil1 was investigated through morphological and genetic analysis. Moreover, by comparing lil1-1 mutant and wild-type individuals grown under drought stress, the effect of BR reduction on the response to drought stress was examined. lil1-1 is a novel allele of the brassinosteroid-deficient dwarf1 (brd1) gene, encoding a brassinosteroid C-6 oxidase. We show in this study that lil1 is epistatic to nana plant1 (na1), a BR gene involved in earlier steps of the pathway. The lill-1 mutation causes alteration in the root gravitropic response, leaf epidermal cell density, epicuticular wax deposition and seedling adaptation to water scarcity conditions. Lack of active BR molecules in maize causes a pleiotropic effect on plant development and improves seedling tolerance of drought. BR-deficient maize mutants can thus be instrumental in unravelling novel mechanisms on which plant adaptations to abiotic stress are based.
Agid:
6245788