RESUMEN
Improving salinity tolerance in the most widely cultivated cereal, bread wheat (Triticum aestivum L.), is essential to increase grain yields on saline agricultural lands. A Portuguese landrace, Mocho de Espiga Branca accumulates up to sixfold greater leaf and sheath sodium (Na+ ) than two Australian cultivars, Gladius and Scout, under salt stress in hydroponics. Despite high leaf and sheath Na+ concentrations, Mocho de Espiga Branca maintained similar salinity tolerance compared to Gladius and Scout. A naturally occurring single nucleotide substitution was identified in the gene encoding a major Na+ transporter TaHKT1;5-D in Mocho de Espiga Branca, which resulted in a L190P amino acid residue variation. This variant prevents Mocho de Espiga Branca from retrieving Na+ from the root xylem leading to a high shoot Na+ concentration. The identification of the tissue-tolerant Mocho de Espiga Branca will accelerate the development of more elite salt-tolerant bread wheat cultivars.
Asunto(s)
Proteínas de Plantas/genética , Brotes de la Planta/metabolismo , Sodio/metabolismo , Triticum/genética , Triticum/metabolismo , Animales , Femenino , Regulación de la Expresión Génica de las Plantas , Modelos Moleculares , Oocitos/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Brotes de la Planta/genética , Polimorfismo de Nucleótido Simple , Antiportadores de Potasio-Hidrógeno/química , Antiportadores de Potasio-Hidrógeno/genética , Antiportadores de Potasio-Hidrógeno/metabolismo , Tolerancia a la Sal/genética , Xenopus laevis , Xilema/genética , Xilema/metabolismoRESUMEN
Plant cells maintain a low luminal pH in the trans-Golgi-network/early endosome (TGN/EE), the organelle in which the secretory and endocytic pathways intersect. Impaired TGN/EE pH regulation translates into severe plant growth defects. The identity of the proton pump and proton/ion antiporters that regulate TGN/EE pH have been determined, but an essential component required to complete the TGN/EE membrane transport circuit remains unidentified - a pathway for cation and anion efflux. Here, we have used complementation, genetically encoded fluorescent sensors, and pharmacological treatments to demonstrate that Arabidopsis cation chloride cotransporter (CCC1) is this missing component necessary for regulating TGN/EE pH and function. Loss of CCC1 function leads to alterations in TGN/EE-mediated processes including endocytic trafficking, exocytosis, and response to abiotic stress, consistent with the multitude of phenotypic defects observed in ccc1 knockout plants. This discovery places CCC1 as a central component of plant cellular function.
Asunto(s)
Arabidopsis/genética , Proteínas de Transporte de Catión/genética , Cationes/metabolismo , Cloruros/metabolismo , Endosomas/metabolismo , Regulación de la Expresión Génica de las Plantas , Red trans-Golgi/genética , Arabidopsis/fisiología , Endocitosis , Homeostasis , Concentración de Iones de Hidrógeno , Red trans-Golgi/metabolismoRESUMEN
Cytochrome P450 enzymes encoded by MORE AXILLARY GROWTH1 (MAX1)-like genes produce most of the structural diversity of strigolactones during the final steps of strigolactone biosynthesis. The diverse copies of MAX1 in Oryza sativa provide a resource to investigate why plants produce such a wide range of strigolactones. Here we performed in silico analyses of transcription factors and microRNAs that may regulate each rice MAX1, and compared the results with available data about MAX1 expression profiles and genes co-expressed with MAX1 genes. Data suggest that distinct mechanisms regulate the expression of each MAX1. Moreover, there may be novel functions for MAX1 homologues, such as the regulation of flower development or responses to heavy metals. In addition, individual MAX1s could be involved in specific functions, such as the regulation of seed development or wax synthesis in rice. Our analysis reveals potential new avenues of strigolactone research that may otherwise not be obvious.
Asunto(s)
Oryza/genética , Proteínas de Plantas/genética , Factores de Transcripción/genética , Proteínas de Arabidopsis/genética , Simulación por Computador , Regulación de la Expresión Génica de las Plantas , Ontología de Genes , Redes Reguladoras de Genes , Compuestos Heterocíclicos con 3 Anillos/metabolismo , Lactonas/metabolismo , MicroARNs/genética , Oryza/crecimiento & desarrollo , Proteínas de Plantas/metabolismo , Regiones Promotoras Genéticas , ARN de Planta/genética , Factores de Transcripción/metabolismoRESUMEN
During plant growth, sodium (Na+) in the soil is transported via the xylem from the root to the shoot. While excess Na+ is toxic to most plants, non-toxic concentrations have been shown to improve crop yields under certain conditions, such as when soil K+ is low. We quantified grain Na+ across a barley genome-wide association study panel grown under non-saline conditions and identified variants of a Class 1 HIGH-AFFINITY-POTASSIUM-TRANSPORTER (HvHKT1;5)-encoding gene responsible for Na+ content variation under these conditions. A leucine to proline substitution at position 189 (L189P) in HvHKT1;5 disturbs its characteristic plasma membrane localisation and disrupts Na+ transport. Under low and moderate soil Na+, genotypes containing HvHKT1:5P189 accumulate high concentrations of Na+ but exhibit no evidence of toxicity. As the frequency of HvHKT1:5P189 increases significantly in cultivated European germplasm, we cautiously speculate that this non-functional variant may enhance yield potential in non-saline environments, possibly by offsetting limitations of low available K+.