Soybean and casein hydrolysates induce grapevine immune responses and resistance against Plasmopara viticola

Abstract

Plasmopara viticola, the causal agent of grapevine downy mildew, is one of the most devastating grape pathogen in Europe and North America. Although phytochemicals are used to control pathogen infections, the appearance of resistant strains and the concern for possible adverse effects on environment and human health are increasing the search for alternative strategies. In the present investigation, we successfully tested two protein hydrolysates from soybean (soy) and casein (cas) to trigger grapevine resistance against P. viticola. On Vitis vinifera cv. Marselan plants, the application of soy and cas reduced the infected leaf surface by 76 and 63%, as compared to the control, respectively. Since both hydrolysates might trigger the plant immunity, we investigated their ability to elicit grapevine defense responses. On grapevine cell suspensions, a different free cytosolic calcium signature was recorded for each hydrolysate, whereas a similar transient phosphorylation of two MAP kinases of 45 and 49 kDa was observed. These signaling events were followed by transcriptome reprogramming, including the up-regulation of defense genes encoding pathogenesis-related (PR) proteins and the stilbene synthase enzyme responsible for the biosynthesis of resveratrol, the main grapevine phytoalexin. Liquid chromatography analyses confirmed the production of resveratrol and its dimer metabolites, δ- and ε-viniferins. Overall, soy effects were more pronounced as compared to the cas ones. Both hydrolysates proved to act as elicitors to enhance grapevine immunity against pathogen attack.

Crude garlic extract significantly inhibits replication of grapevine viruses

“…The expression of VvPR1 , VvPR4 and VvPR10 in field‐grown and potted plants was also significantly induced after treatment with the diluted garlic extract. These results are similar to those observed in biogenic elicitor‐induced grapevine defence responses against fungi (Aziz et al , , ; Trotel‐Aziz et al , ; Lachhab et al , ). Some biogenic elicitors have been shown to stimulate the activity of antioxidant enzymes (Zhu et al , ; Naz et al , ).…”

Elicitation of resistance responses in grapefruit and lemon fruits treated with a pomegranate peel extract

“…The primed state has been related to increased, more efficient, activation of the defence response and enhanced resistance to a challenging stress (Aranega‐Bou et al ., ). In previous studies, the up‐regulation of both MAPKK and MAPK was observed in grapefruit, tomato fruit and grapevines treated with Metschnikowia fructicola , Cryptococcus laurentii and protein hydrolysates, respectively (Jiang et al ., ; Hershkovitz et al ., ; Lachhab et al ., ). In general, MAPK cascades transfer signals from upstream receptors to downstream cellular effectors with the consequent modification of downstream signalling proteins (Zhang & Klessig, ).…”

“…Similarly, catechol and protocatechuic acid induced resistance of red onion to Colletotrichum circinans (Link et al ., ; Walker & Stahmann, ). Moreover, an increased level of antifungal phenols at the infection site as a consequence of increased activity of the enzyme phenylalanine ammonia lyase (PAL) has been demonstrated for several host–pathogen combinations (Lachhab et al ., ; Fallanaj et al ., ).…”

The Effect of Hydrolysis and Protein Source on the Efficacy of Protein Hydrolysates as Plant Resistance Inducers against Powdery Mildew

“…In addition, guar enzymatic hydrolysates did not affect conidia germination on leaf disks, suggesting a mode of action mainly based on the stimulation of plant resistance mechanisms, as observed for other protein extracts. Indeed, peptide fragments of different origin have been shown to elicit grapevine defence mechanisms by the up-regulation of defence-related genes [24][25][26][27]. However, further analysis will be required to demonstrate how these peptide sequences could be involved in plant immunity regulation.…”

“…Moreover, peptide fragments can act as inducers of innate plant immunity. For example, casein and soybean hydrolysates have been shown to elicit grapevine defence mechanisms against downy mildew and grey mould by the up-regulation of PR genes [24,25]. Likewise, a protein derivative was effective in controlling courgette powdery mildew and grapevine [26], and activated the expression of defence-related genes in grapevine, suggesting the stimulation of plant resistance mechanisms [27].…”