Dissecting the susceptibility/resistance mechanism of Vitis vinifera for the future control of downy mildew

23CO.NA.VI. 2020 – 8° Convegno Nazionale di Viticoltura, Udine, Italy, July 5-7, 2021openInternationalBothThe Eurasian grapevine (Vitis vinifera), a species cultivated worldwide for high-quality wine production, is extremely susceptible to the agent of downy mildew, Plasmopara viticola. Nevertheless, germplasm from Georgia (Southern Caucasus, the first grapevine domestication centre), characterized by a high genetic variability, showed resistance traits to P. viticola. The cultivar Mgaloblishvili exhibited the most promising phenotype in terms of resistance against P. viticola. Its defence response results in: i) low disease intensity; ii) low sporulation; iii) damaged mycelium; iv) production of antimicrobial compounds such as volatile organic compounds (VOCs), whose effectiveness on the pathogen was evaluated by leafdisc assays. At the transcriptomic level, its resistance mechanism is determined by the differential expression of both resistance and susceptible genes. The resistance genes are related to: i) pathogen recognition through PAMP, DAMP and effector receptors; ii) ethylene signalling pathway; iii) synthesis of antimicrobial compounds (VOCs) and fungal wall degrading enzymes; iv) development of structural barriers (cell wall reinforcement). The first putative susceptible gene was the transcription factor VviLBDIf7 gene, whose validation was carried out by dsRNA (double-stranded RNA) assay. In this work, these unique results on plant-pathogen interaction are reviewed with the aim of developing new strategies to control the disease.openRicciardi, Valentina; Marcianò, Demetrio; Sargolzaei, Maryam; Marrone Fassolo, Elena; Fracassetti, Daniela; Brilli, Matteo; Moser, Mirko; Vahid, Shariati J.; Tavakole, Elahe; Maddalena, Giuliana; Passera, Alessandro; Casati, Paola; Pindo, Massimo; Cestaro, Alessandro; Costa, Alex; Bonza, Maria Cristina; Maghradze, David; Tirelli, Antonio; Failla, Osvaldo; Bianco, Piero Attilio; Quaglino, Fabio; Toffolatti, Silvia Laura; De Lorenzis, GabriellaRicciardi, V.; Marcianò, D.; Sargolzaei, M.; Marrone Fassolo, E.; Fracassetti, D.; Brilli, M.; Moser, M.; Vahid, S.J.; Tavakole, E.; Maddalena, G.; Passera, A.; Casati, P.; Pindo, M.; Cestaro, A.; Costa, A.; Bonza, M.C.; Maghradze, D.; Tirelli, A.; Failla, O.; Bianco, P.A.; Quaglino, F.; Toffolatti, S.L.; De Lorenzis, G

The Barley <i>Uniculme4 </i>Gene Encodes a BLADE-ON-PETIOLE-Like Protein That Controls Tillering and Leaf Patterning

Tillers are vegetative branches that develop from axillary buds located in the leaf axils at the base of many grasses. Genetic manipulation of tillering is a major objective in breeding for improved cereal yields and competition with weeds. Despite this, very little is known about the molecular genetic bases of tiller development in important Triticeae crops such as barley (Hordeum vulgare) and wheat (Triticum aestivum). Recessive mutations at the barley Uniculme4 (Cul4) locus cause reduced tillering, deregulation of the number of axillary buds in an axil, and alterations in leaf proximal-distal patterning. We isolated the Cul4 gene by positional cloning and showed it encodes a BTB-ankyrin protein closely related to Arabidopsis BLADE-ON-PETIOLE1 (BOP1) and BOP2. Morphological, histological and in situ RNA expression analyses indicate that Cul4 acts at axil and leaf boundary regions to control axillary bud differentiation, as well as development of the ligule, which separates the distal blade and proximal sheath of the leaf. As the first functionally characterized BOP gene in monocots, Cul4 suggests partial conservation of BOP gene function between dicots and monocots, while phylogenetic analyses highlight distinct evolutionary patterns in the two lineages