RESUMO
Commercially improved crop performance under drought conditions has been challenging because of the complexity of the trait and the multitude of factors that influence yield. Here we report the results of a functional genomics approach that identified a transcription factor from the nuclear factor Y (NF-Y) family, AtNF-YB1, which acts through a previously undescribed mechanism to confer improved performance in Arabidopsis under drought conditions. An orthologous maize transcription factor, ZmNF-YB2, is shown to have an equivalent activity. Under water-limited conditions, transgenic maize plants with increased ZmNF-YB2 expression show tolerance to drought based on the responses of a number of stress-related parameters, including chlorophyll content, stomatal conductance, leaf temperature, reduced wilting, and maintenance of photosynthesis. These stress adaptations contribute to a grain yield advantage to maize under water-limited environments. The application of this technology has the potential to significantly impact maize production systems that experience drought.
Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/genética , Fator de Ligação a CCAAT/fisiologia , Desastres , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas/genética , Fatores de Transcrição/fisiologia , Água , Zea mays/genética , Proteínas de Arabidopsis/genética , Fator de Ligação a CCAAT/genética , Genômica , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Subunidades Proteicas/genética , Subunidades Proteicas/fisiologia , Fatores de Transcrição/genética , Zea mays/crescimento & desenvolvimentoRESUMO
The outer epidermal plant cell wall and cuticle play an important role in regulating both abiotic and biotic interactions between the plant and its environment. In addition to acting as a protective barrier that limits water loss, the effects of detrimental irradiation and invasion by pathogens, the epidermis also offers an interface that is inert to interactions between organs and ensures proper separation and expansion of organs at the growing points of the plant. Here, we describe the molecular cloning and characterization of HOTHEAD (HTH), a gene required to limit cellular interactions between contacting epidermal cells during floral development. HTH is a member of a small gene family in Arabidopsis and encodes an enzyme related to a group of FAD-containing oxidoreductases that have been described in several other species. Characterization of 11 independently derived mutant alleles suggests that key amino acids are shared between these related groups of enzymes and identify a cluster of other functionally important residues that are highly conserved only within the Arabidopsis gene family. Our findings add this new type of enzyme to a growing list of enzymes that have been shown to be involved in regulating post-genital organ fusion. Expression analysis of the HTH gene shows that it is expressed in all tissues tested, including roots, and is not epidermis-specific. Furthermore, the sequence data unequivocally show that none of the alleles isolated are epigenetic alleles as suggested by genetic behavior previously observed at this locus.