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Agricultural practices in grapevines management include water restrictions due to its positive effect on wine quality, especially when applied at fruit ripening. Although the effects of water stress in some groups of phytohormones have already been described in leaves and whole grapes, information regarding tissue-specific variations in hormones during ripening in grapes is scarce. Field-grown grapevines from the cv. “Merlot” were subjected to two differential water supplies, including only rainfed, non-irrigated vines (T0) and vines additionally irrigated with 25Lweek−1 vine−1 (T1). Tissue-specific variations in the hormonal profiling of grapes [including changes in the contents of abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), the ethylene precursor 1-amino-cyclopropane-1-carboxylic acid (ACC), the auxin indole-3-acetic acid, gibberellins 1, 3, 4, and 7 (GA1, GA3, GA4, and GA7), the cytokinins trans-zeatin, and 2-isopentenyl adenine, including as well their respective ribosylated forms] were periodically evaluated from veraison to harvest. The hormonal profiling in leaves was also measured at the beginning and end of the season for comparison. Results showed that grape growth dynamics were transiently affected by the differences in water regimes, the increased water supply leading to an accelerated growth, slightly reduced accumulation of sugars, and transiently lowered pH, although grape quality did not differ between treatments at harvest. Hormonal profiling of whole berries did not reveal any difference in the endogenous contents of phytohormones between treatments, except for a transient decrease in GA4 contents in T1 compared to T0 vines, which was not confirmed at the tissular level. Hormonal profiling at the tissue level highlighted a differential accumulation of phytohormones during ripening in berry tissues, with pulps being particularly poor in ABA, JA, and SA contents, seeds particularly accumulating ACC, gibberellins, and zeatin-type cytokinins, and the skin being particularly rich in auxin and active cytokinins. Changes in water supply led to very small and transient changes in the endogenous contents of phytohormones in the seeds, pulp, and skin of berries, the most remarkable variations being observed in cytokinin contents, which increased earlier [between 5 and 12days after veraison (DAV)] but later kept more constant in the skin from T1 compared to T0 vines and were also 3-fold higher at 40 DAV in seeds of T1 compared to T0 vines. It is concluded that small changes in water supply can trigger hormonal-driven physiological adjustments at the tissular level affecting the evolution of fruit growth and quality throughout grape berry ripening.

Agricultural practices in grapevines management include water restrictions due to its positive effect on wine quality, especially when applied at fruit ripening. Although the effects of water stress in some groups of phytohormones have already been described in leaves and whole grapes, information regarding tissue-specific variations in hormones during ripening in grapes is scarce. Field-grown grapevines from the cv. "Merlot" were subjected to two differential water supplies, including only rainfed, non-irrigated vines (T0) and vines additionally irrigated with 25Lweek−1 vine−1 (T1). Tissue-specific variations in the hormonal profiling of grapes [including changes in the contents of abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), the ethylene precursor 1-amino-cyclopropane-1-carboxylic acid (ACC), the auxin indole-3-acetic acid, gibberellins 1, 3, 4, and 7 (GA1, GA3, GA4, and GA7), the cytokinins trans -zeatin, and 2-isopentenyl adenine, including as well their respective ribosylated forms] were periodically evaluated from veraison to harvest. The hormonal profiling in leaves was also measured at the beginning and end of the season for comparison. Results showed that grape growth dynamics were transiently affected by the differences in water regimes, the increased water supply leading to an accelerated growth, slightly reduced accumulation of sugars, and transiently lowered pH, although grape quality did not differ between treatments at harvest. Hormonal profiling of whole berries did not reveal any difference in the endogenous contents of phytohormones between treatments, except for a transient decrease in GA4 contents in T1 compared to T0 vines, which was not confirmed at the tissular level. Hormonal profiling at the tissue level highlighted a differential accumulation of phytohormones during ripening in berry tissues, with pulps being particularly poor in ABA, JA, and SA contents, seeds particularly accumulating ACC, gibberellins, and zeatin-type cytokinins, and the skin being particularly rich in auxin and active cytokinins. Changes in water supply led to very small and transient changes in the endogenous contents of phytohormones in the seeds, pulp, and skin of berries, the most remarkable variations being observed in cytokinin contents, which increased earlier [between 5 and 12days after veraison (DAV)] but later kept more constant in the skin from T1 compared to T0 vines and were also 3-fold higher at 40 DAV in seeds of T1 compared to T0 vines. It is concluded that small changes in water supply can trigger hormonal-driven physiological adjustments at the tissular level affecting the evolution of fruit growth and quality throughout grape berry ripening. [ABSTRACT FROM AUTHOR]

Abstract: An alpha-expansin (RiEXPA1) gene was cloned and sequenced from raspberry. Expression of RiEXPA1 in different ripening stages of raspberry fruits has been detected. Northern blotting showed that the level of RiEXPA1 transcript accumulation increased with fruit ripening and the highest level of expression appeared at the later stages of ripening. This indicates that expression of RiEXPA1 is closely correlated with the ripening and softening of raspberry fruits. In order to determine whether expression of the RiEXPA1 was regulated by ethylene, we cloned and sequenced a 1-aminocyclo-propane-1-carboxylic acid synthase cDNA (RiACS1) that encodes the rate-limiting enzyme for ethylene production. Transcript accumulation of RiACS1 was detected at a low level only in the later stage of fruit ripening. This reveals that ethylene is not a regulatory factor of RiEXPA1 expression in raspberry fruit. The results of this investigation suggest that the expression of RiACS1 gene during ripening resembles that of non-climacteric fruits. [Copyright &y& Elsevier]

Notwithstanding the economic importance of non-climacteric fruits like grape and strawberry, little is known about the mechanisms that regulate their ripening. Up to now no growth regulator has emerged with a primary role similar to that played by ethylene in the ripening of the climacteric fruits. Strawberries can produce ethylene, although in limited amounts. Two cDNAs coding for enzymes of the ethylene biosynthetic pathway (i.e. FaACO1 and FaACO2), and three cDNAs encoding different ethylene receptors have been isolated. Two receptors (i.e. FaEtr1 and FaErs1) belong to the type-I while the third (i.e. FaEtr2) belongs to the type-II group. The expression of both the ACO and the receptor-encoding genes has been studied in fruits at different stages of development and in fruits treated with hormones (i.e. ethylene and the auxin analogue NAA). All the data thus obtained have been correlated to the known data about ethylene production by strawberry fruits. Interestingly, a good correlation has resulted between the expression of the genes described in this work and the data of ethylene production. In particular, similarly to what occurs during climacteric fruit ripening, there is an increased synthesis of receptors concomitant with the increased synthesis of ethylene in strawberries as well. Moreover, the receptors mostly expressed in ripening strawberries are the type-II ones, that is those with a degenerate histidine–kinase domain. Since the latter domain is thought to establish a weaker link to the CTR1 proteins, even the little ethylene produced by ripening strawberries might be sufficient to trigger ripening-related physiological responses. [ABSTRACT FROM PUBLISHER]

The cultivated strawberry (Fragaria × ananassa), an allo-octoploid with non-climacteric fleshy fruits, is a popular Rosaceae horticultural crop worldwide that is mainly propagated via stolons during cultivation. Woodland strawberry (Fragaria vesca), one of the four diploid progenitor species of cultivated strawberry, is widely used as a model plant in the study of Rosaceae fruit trees, non-climacteric fruits and stolons. One GRAS transcription factor has been shown to regulate stolon formation; the other GRAS proteins in woodland strawberry remain unknown. In this study, we identified 54 FveGRAS proteins in woodland strawberry, and divided them into 14 subfamilies. Conserved motif analysis revealed that the motif composition of FveGRAS proteins was conserved within each subfamily, but diverged widely among subfamilies. We found 56 orthologous pairs of GRAS proteins between woodland strawberry and Arabidopsis thaliana, 47 orthologous pairs between woodland strawberry and rice and 92 paralogous pairs within woodland strawberry. The expression patterns of FveGRAS genes in various organs and tissues, and changes therein under cold, heat and GA3 treatments, were characterized using transcriptomic analysis. The results showed that 34 FveGRAS genes were expressed with different degrees in at least four organs, including stolons; only a few genes displayed organ-specific expression. The expression levels of 16 genes decreased, while that of four genes increased during fruit ripening; FveGRAS54 showed the largest increase in expression. Under cold, heat and GA3 treatments, around half of the FveGRAS genes displayed increased or decreased expression to some extent, suggesting differing functions of these FveGRAS genes in the responses to cold, heat and GAs. This study provides insight into the potential functions of FveGRAS genes in woodland strawberry. A few FveGRAS genes were identified as candidate genes for further study, in terms of their functions in stolon formation, fruit ripening and abiotic stresses. [ABSTRACT FROM AUTHOR]