Nitric oxide in the physiology and quality of fleshy fruits

Abstract

Fruits are unique to flowering plants and confer a selective advantage as they facilitate seed maturation and dispersal. In fleshy fruits, development and ripening are associated with numerous structural, biochemical, and physiological changes, including modifications in the general appearance, texture, flavor, and aroma, which ultimately convert the immature fruit into a considerably more attractive and palatable structure for seed dispersal by animals. Treatment with exogenous nitric oxide (NO) delays fruit ripening, prevents chilling damage, promotes disease resistance, and enhances the nutritional value. The ripening process is influenced by NO, which operates antagonistically to ethylene, but it also interacts with other regulatory molecules such as abscisic acid, auxin, jasmonic acid, salicylic acid, melatonin, and hydrogen sulfide. NO content progressively declines during fruit ripening, with concomitant increases in protein nitration and nitrosation, two post-translational modifications that are promoted by reactive nitrogen species. Dissecting the intimate interactions of NO with other ripening-associated factors, including reactive oxygen species, antioxidants, and the aforementioned phytohormones, remains a challenging subject of research. In this context, integrative ‘omics’ and gene-editing approaches may provide additional knowledge of the impact of NO in the regulatory processes involved in controlling physiology and quality traits in both climacteric and non-climacteric fruits.

LbNR-Derived Nitric Oxide Delays Lycium Fruit Coloration by Transcriptionally Modifying Flavonoid Biosynthetic Pathway

“…NO promotes leaf expansion, represses floral transition, stimulates light-dependent germination, promotes de-etiolation, inhibits maturation, and senescence, ( Bruand and Meilhoc, 2019 ). Like in pepper, tomato, strawberry, and avocado plants ( Gonzalez-Gordo et al., 2019 ; Palma et al., 2019 ), the present work indicated that the release of NO progressively declined during fruit ripening in Lycium plants, a medicinal and edible species. These results may show that it is a conserved event for endogenous NO production decline during fresh fruit ripening.…”

“…These results may show that it is a conserved event for endogenous NO production decline during fresh fruit ripening. In other words, NO has been demonstrated to delay fruit ripening generally, independently on whether fruits are climacteric or nonclimacteric ( Palma et al., 2019 ). Integrating the results that the LbNR transcript amount is significantly positively correlated with the NO release during fruit ripening and that the VIGS-mediated LbNR gene silencing significantly decreased the NO production in ripe Lycium fruits, we could conclude that NR was partially responsible for NO biosynthesis in Lycium plants.…”

“…in Lycium plants. To our knowledge, this is the first report that NR-derived NO formation has been involved in fruit maturation of medicinal plant (Manjunatha et al, 2010;Palma et al, 2019). Coloration of fresh fruits is a natural and excellent phenotypic marker for studying the mechanisms behind the regulation of fruit ripening and pigment metabolism.…”

“…The available data have established the role of NO in senescence delay, in which NO acts primarily but not solely by limiting ethylene emission, resulting in delayed ripening ( Manjunatha et al., 2010 ; Manjunatha et al., 2012 ; Bodanapu et al., 2016 ; Yang et al., 2016 ; Palma et al., 2019 ). NO application can also improve fruit quality, cold resistance, secondary metabolite biosynthesis, shelf life, and disease resistance ( Li et al., 2017 ; Corpas et al., 2018 ; Corpas and Palma, 2018 ; Palma et al., 2019 ). Moreover, factors that induce NO generation can suppress fruit softening ( Guo et al., 2018 ).…”

Antioxidant Profile of Pepper (<em>Capsicum annuum</em> L.) Fruits Containing Diverse Levels of Capsaicinoids

“…Excepting Alegría which has been scarcely used for research purposes, reports on the other three varieties can be found in the literature. Thus, Melchor variety has been used to decipher the mechanisms involved in fruit ripening [18,39,66,67] where some of their antioxidant system have been reported to be involved [68]. Variety Piquillo was used as model to address the effects triggered by infection with Verticillum [69][70][71][72] and how to protect pepper plants against it through diverse practices [73,74], as well as to investigate the effect of sanitized sewage sludge on the growth, yield, fruit quality, soil microbial community and the physiology of pepper plants [75,76].…”