RESUMEN
The S-RNase-based gametophytic self-incompatibility (GSI) reproduction barrier is important for maintaining genetic diversity in species of the families Solanaceae, Plantaginaceae and Rosaceae. Among the plant taxa with S-RNase-based GSI, Prunus species in the family Rosaceae exhibit Prunus-specific self-incompatibility (SI). Although pistil S and pollen S determinants have been identified, the mechanism underlying SI remains uncharacterized in Prunus species. A putative pollen-part modifier was identified in this study. Disruption of this modifier supposedly confers self-compatibility (SC) to sweet cherry (Prunus avium) 'Cristobalina'. To identify the modifier, genome re-sequencing experiments were completed involving sweet cherry individuals from 18 cultivars and 43 individuals in two segregating populations. Cataloging of subsequences (35 bp kmers) from the obtained genomic reads, while referring to the mRNA sequencing data, enabled the identification of a candidate gene [M locus-encoded GST (MGST)]. Additionally, the insertion of a transposon-like sequence in the putative MGST promoter region in 'Cristobalina' down-regulated MGST expression levels, probably leading to the SC of this cultivar. Phylogenetic, evolutionary and gene expression analyses revealed that MGST may have undergone lineage-specific evolution, and the encoded protein may function differently from the corresponding proteins encoded by GST orthologs in other species, including members of the subfamily Maloideae (Rosaceae). Thus, MGST may be important for Prunus-specific SI. The identification of this novel modifier will expand our understanding of the Prunus-specific GSI system. We herein discuss the possible functions of MGST in the Prunus-specific GSI system.
Asunto(s)
Genes Modificadores/genética , Genoma de Planta/genética , Prunus avium/genética , Ribonucleasas/metabolismo , Autoincompatibilidad en las Plantas con Flores/genética , Biblioteca de Genes , Mutación , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Polen/genética , Polen/fisiología , Prunus avium/enzimología , Prunus avium/fisiología , Ribonucleasas/genética , Análisis de Secuencia de ARNRESUMEN
Plant SNF1-related protein kinase 2 (SnRK2) and protein phosphatase 2C (PP2C) family members are core components of the ABA signal transduction pathway. SnRK2 and PP2C proteins have been suggested to play crucial roles in fruit ripening and improving plant tolerance to drought stress, but supporting genetic information has been lacking in sweet cherry (Prunus avium L.). Here, we cloned six full-length SnRK2 genes and three full-length PP2C genes from sweet cherry cv. Hong Deng. Quantitative PCR analysis revealed that PacSnRK2.2, PacSnRK2.3, PacSnRK2.6, and PacPP2C1-3 were negatively regulated in fruits in response to exogenous ABA treatment, PacSnRK2.4 and PacSnRK2.5 were upregulated, and PacSnRK2.1 expression was not affected. The ABA treatment also significantly promoted the accumulation of anthocyanins in sweet cherry fruit. The expression of all PacSnRK2 and PacPP2C genes was induced by dehydration stress, which also promoted the accumulation of drought stress signaling molecules in the sweet cherry fruits, including ABA, soluble sugars, and anthocyanin. Furthermore, a yeast two-hybrid analysis demonstrated that PacPP2C1 interacts with all six PacSnRK2s, while PacPP2C3 does not interact with PacSnRK2.5. PacPP2C2 does not interact with PacSnRK2.1 or PacSnRK2.4. These results indicate that PacSnRK2s and PacPP2Cs may play a variety of roles in the sweet cherry ABA signaling pathway and the fruit response to drought stress.
Asunto(s)
Regulación Enzimológica de la Expresión Génica/fisiología , Regulación de la Expresión Génica de las Plantas/fisiología , Fosfoenolpiruvato Carboxilasa , Proteínas de Plantas , Proteínas Serina-Treonina Quinasas , Prunus avium , Estrés Fisiológico/fisiología , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacología , Clonación Molecular , Deshidratación/genética , Deshidratación/metabolismo , Perfilación de la Expresión Génica , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Fosfoenolpiruvato Carboxilasa/biosíntesis , Fosfoenolpiruvato Carboxilasa/genética , Proteínas de Plantas/biosíntesis , Proteínas de Plantas/genética , Proteínas Serina-Treonina Quinasas/biosíntesis , Proteínas Serina-Treonina Quinasas/genética , Prunus avium/enzimología , Prunus avium/genética , Estrés Fisiológico/efectos de los fármacosRESUMEN
To elucidate metabolism of ascorbic acid (AsA) in sweet cherry fruit (Prunus avium 'Hongdeng'), we quantified AsA concentration, cloned sequences involved in AsA metabolism and investigated their mRNA expression levels, and determined the activity levels of selected enzymes during fruit development and maturation. We found that AsA concentration was highest at the petal-fall period (0 days after anthesis) and decreased progressively during ripening, but with a slight increase at maturity. AsA did nevertheless continue to accumulate over time because of the increase in fruit fresh weight. Full-length cDNAs of 10 genes involved in the L-galactose pathway of AsA biosynthesis and 10 involved in recycling were obtained. Gene expression patterns of GDP-L-galactose phosphorylase (GGP2), L-galactono-1, 4-lactone dehydrogenase (GalLDH), ascorbate peroxidase (APX3), ascorbate oxidase (AO2), glutathione reductase (GR1), and dehydroascorbate reductase (DHAR1) were in accordance with the AsA concentration pattern during fruit development, indicating that genes involved in ascorbic acid biosynthesis, degradation, and recycling worked in concert to regulate ascorbic acid accumulation in sweet cherry fruit.
Asunto(s)
Ácido Ascórbico/metabolismo , Frutas/metabolismo , Prunus avium/metabolismo , Ascorbato Oxidasa/genética , Ascorbato Oxidasa/metabolismo , Ascorbato Peroxidasas/genética , Ascorbato Peroxidasas/metabolismo , Metabolismo de los Hidratos de Carbono/genética , Metabolismo de los Hidratos de Carbono/fisiología , ADN Complementario/genética , Frutas/enzimología , Frutas/genética , Regulación de la Expresión Génica de las Plantas/genética , Glutatión Reductasa/genética , Glutatión Reductasa/metabolismo , Monoéster Fosfórico Hidrolasas/genética , Monoéster Fosfórico Hidrolasas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Prunus avium/enzimología , Prunus avium/genéticaRESUMEN
The aim of this study was to investigate the biochemical and metabolic changes, related to oxidative stress, ethylene and respiration, cell wall modification and primary metabolism, between a high ('Prime Giant') and a low ('Cristalina') cracking susceptible sweet cherry cultivar during growth and ripening. While cherries are referred as a non-climacteric fruit, our results show that an increase of endogenous ethylene production at earlier fruit developmental stages is parallel to colour development and softening during growth. Higher cracking susceptibility was clearly associated to a higher fruit growth rate and accompanied by an increase net CO2 and ethylene production, on a cherry basis, leading to an enhanced accumulation of oxidative stress markers (i.e. H2O2 and MDA). As observed in other fruit species (i.e. tomatoes) higher cracking susceptibility was also related to enhanced activity of cell wall-modifying enzymes which in turn occurred in parallel to the ethylene rise. Overall, these results suggest that cracking development may be a more complex phenomenon than a mere consequence of altered fruit water absorption or turgor and point out the importance of ethylene on sweet cherry ripening and cracking development.