The characterization of a novel mutant, named Pinalate, derived from the orange (Citrus sinensis L. Osbeck) Navelate, which produces distinctive yellow fruits instead of the typical bright orange colouration, is reported. The carotenoid content and composition, and ABA content in leaf and flavedo tissue (coloured part of the skin) of fruits at different developmental and maturation stages were analysed. No important differences in leaf carotenoid pattern of both phenotypes were found. However, an unusual accumulation of linear carotenes (phytoene, phytofluene and zeta- carotene) was detected in the flavedo of Pinalate. As fruit maturation progressed, the flavedo of mutant fruit accumulated high amounts of these carotenes and the proportion of cyclic and oxygenated carotenoids was substantially lower than in the parental line. Full-coloured fruit of Pinalate contained about 44% phytoene, 21% phytofluene, 25% zeta-carotene, and 10% of xanthophylls, whereas, in Navelate, 98% of total carotenoids were xanthophylls and apocarotenoids. The ABA content in the flavedo of Pinalate mature fruit was 3-6 times lower than in the corresponding tissue of Navelate, while no differences were found in leaves. Other maturation processes were not affected in Pinalate fruit. Taken together, the results indicate that Pinalate is a fruit-specific alteration defective in zeta-carotene desaturase or in zeta-carotene desaturase-associated factors. Possible mechanisms responsible for the Pinalate phenotype are discussed. Because of the abnormal fruit-specific carotenoid complement and ABA deficiency, Pinalate may constitute an excellent system for the study of carotenogenesis in Citrus and the involvement of ABA in fruit maturation and stress responses.

Glyphosate-based herbicide products are the most widely used broad-spectrum herbicides in the world for postemergent weed control. There are ever-increasing concerns that glyphosate, if not used judiciously, may cause adverse nontarget impacts in agroecosystems. The purpose of this brief review is to present and discuss the state of knowledge with respect to its persistence in the environment, possible effects on crop health, and impacts on crop nutrition.

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Water stress affects many agronomic traits that may be regulated by the phytohormone abscisic acid (ABA). Within these traits, loss of fruit quality becomes important in many citrus cultivars that develop peel damage in response to dehydration. To study peel dehydration transcriptional responsiveness in harvested citrus fruit and the putative role of ABA in this process, this study performed a comparative large-scale transcriptional analysis of water-stressed fruits of the wild-type Navelate orange (Citrus sinesis L. Osbeck) and its spontaneous ABA-deficient mutant Pinalate, which is more prone to dehydration and to developing peel damage. Major changes in gene expression occurring in the wild-type line were impaired in the mutant fruit. Gene ontology analysis revealed the ability of Navelate fruits to induce the response to water deprivation and di-, tri-valent inorganic cation transport biological processes, as well as repression of the carbohydrate biosynthesis process in the mutant. Exogenous ABA triggered relevant transcriptional changes and repressed the protein ubiquitination process, although it could not fully rescue the physiological behaviour of the mutant. Overall, the results indicated that dehydration responsiveness requires ABA-dependent and -independent signals, and highlight that the ability of citrus fruits to trigger molecular responses against dehydration is an important factor in reducing their susceptibility to developing peel damage.