Metabolic and transcript analysis of the flavonoid pathway in diseased and recovered Nebbiolo and Barbera grapevines (Vitis vinifera L.) following infection by Flavescence dorée phytoplasma

Abstract

Flavescence dorée phytoplasma (FDp) infections seriously affect production and survival of grapevine. We analysed the changes in the flavonoid pathway occurring in two red cultivars, the highly susceptible Barbera and the less susceptible Nebbiolo, following FDp infection. A combination of metabolic and transcript analyses was used to quantify flavonoid compounds and expression of a set of genes involved in their biosynthesis. Quantification of anthocyanins, flavonols, proanthocyanidins and related biosynthetic enzymes was performed over the vegetative season, at four time points, on healthy, infected and recovered plants. A strong activation of anthocyanin accumulation was observed in infected Barbera leaves, while the response was less marked in Nebbiolo. Proanthocyanidins also accumulated mainly in infected Barbera leaves, even if basal proanthocyanidin concentration was higher in healthy and recovered Nebbiolo. Biochemical data were supported by transcript analysis: genes of the stem flavonoid pathway and of the anthocyanin and proanthocyanidin branches were expressed at a higher level in infected than in healthy plants, with a different magnitude between the two cultivars. Based on our results, we hypothesize that flavonoid accumulation is a physiological consequence of FD infection without affecting phytoplasma multiplication, although proanthocyanidin accumulation could help repel further infection by the insect vector.

Candidatus Phytoplasma trifolii (16SrVI) infection modifies the polyphenols concentration in pepper (Capsicum annuum) plant tissues

“…Margaria et al. () suggest that an explanation for the activation of anthocyanins biosynthesis may reside in the sugar concentration increase in the infected leaves, as accumulation of soluble carbohydrates has been reported in phytoplasma‐infected leaves of several host cultivars, and they induce the anthocyanin synthesis pathway. Anthocyanins are particularly important for protecting photosystems from ROS generated by photon‐saturated photosystem in leaf cells, therefore could have an antioxidant role, limiting further oxidative damage (Hoch, Singsaas, & McCown, ; Margaria et al., ).…”

“…Pepper crops can be grown in fields and in greenhouses; however, their average yields are severely impacted by the presence of pests and diseases (Dikilitas, Guldur, Deryaoglu, & Ozcan, ). Besides well‐known fungal and virus pathogens, recently, phytoplasma has become increasingly important as a serious threat in many different crops around the world (Junqueira, Bedendo, & Pascholati, ; Margaria et al., ), and the pepper crop is not the exception. Phytoplasma associated with C. annuum diseases have been reported worldwide, including bell pepper leaf size reduction (16SrIII) in Bolivia, bell and chilli pepper big bud in Iran and the United States, respectively (16SrII and 16SrVI) and pepper witches’ broom (16SrI) in China and México (Arocha et al., ; Faghihi, Taghavi, Safaei, Siampour, & Najafabadi, ; Randall, Bosland, & Hanson, ; Santos‐Cervantes, Chávez‐Medina, Mendez‐Lozano, & Leyva‐Lopez, ; Zheng‐Nan, Zhang, Song, & Wu, ).…”

“…Although few studies have linked the incidence of phytoplasma infection to increase in the phenolic compounds in different crops, such as Malus pumina and Prunus domestica (Musetti, Favali, & Pressacco, ), Zea mays (Junqueira et al., ), Vitis vinifera (Margaria et al., ), Theobroma cacao (Ondobo et al., ) and Vigna radiata (Hameed et al., ), there is insufficient information regarding the effect of phytoplasma over the polyphenols content in the pepper plants. In a more specific manner, biochemical changes at the phenylpropanoid pathway level among different pepper plant tissues are less known.…”

Determination of the Activity Signature of Key Carbohydrate Metabolism Enzymes in Phenolic-rich Grapevine Tissues

“…12,13 By reacting indiscriminately, these compounds both inactivate enzymes and interfere with detection techniques.…”

Conventional and novel approaches for managing “flavescence dorée” in grapevine: knowledge gaps and future prospects

“…A study conducted by Margaria et al . () provided a molecular and biochemical description of the flavonoid pathway in response to FD phytoplasma in infected and recovered plants. This study suggested that accumulation of proanthocyanidins, mainly in healthy and recovered grapevines, could help to minimize further infection by the insect vector (Margaria et al ., ).…”