Transcriptome analysis of peach ? T. deformans interaction in a susceptible genotype

NOVELLO, MARIA ANGELINA; VALENTINI, GABRIEL; DRINCOVICH, MARÍA FABIANA; LARA, MARÍA VALERIA

Salta

Congreso; LV Reunión Anual de SAIB - XIV PABMB. 2019.; 2019

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Prunus persica (L) Batsch, is a tree of great economic importance and is susceptible to numerous diseases including the Peach Leaf Curl?a widely worldwide distributed disease that generates losses ranging between 2.5 and 3 million dollars per year. The causal agent of the disease is the dimorphic fungus Taphrina deformans. The pathogen invades new shoots in early spring when the leaves are young and have a thin cuticle. The symptoms include chlorosis, pink pigmentation, the characteristic curling of the leaf, and ultimately the senescence of the leaves and the tree?s death. Normally, the disease is controlled with agrochemicals, but its high cost, its potential negative impact on animals and humans, and its insufficient control have increased the demand for farming practices that reduce risks to health and the environment, being necessary strategies based on genetically resistant materials. In this work, leaves of the susceptible genotype, DOFI-71.043.018 were inoculated with T. deformans. Hypha development was followed using Gueguen staining. Samples were collected at 0, 12, and 96 h post-inoculation (hpi) and used for RNA extraction. RNAseq analysis was conducted to unravel the early responses of the host. The analysis yielded 357 and 210 differentially expressed genes (DEGs) at 12 and 96 hpi compared to 0 hpi, respectively. Approximately 43% of the DEGs were induced and 57% were repressed in both comparisons. The most represented functional categories were RNA, signaling, hormones, proteins and biotic stress. Regarding RNA, transcription factors (FT) such as WRKY, bHLH, HB, MYB, and zinc fingers FT were differentially expressed. While MYB FTs were induced both at 12 and 96 hpi, bHLH FTs were exclusively up-regulated at 12 hpi. Differences regarding phytohormones were also found; enzymes involved in the ethylene biosynthesis such as ACC oxidase (PRUPE.1G036600) and ACC synthase (PRUPE.2G176900) and involved in jasmonic acid biosynthesis like LOX1 (PRUPE.4G047800) were significantly induced at 12 hpi. Moreover, the metabolism of brassinosteroids was induced at 96 hpi. The increase in these hormones synthesis upon infection could activate defense responses. On the contrary, the abscisic acid biosynthetic pathway was repressed as an early response. The induction of auxin-responsive genes was also detected and could be responsible for some symptoms of the disease. Furthermore, many pathogenesis-related proteins (PR), like Thaumatin-like proteins (PR5), Kunitz proteinase inhibitors (PR6), lipid transfer proteins (PR14), B-1,3-glucanases (PR2), and endochitinases (PR3) were induced exclusively at 12 hpi indicating the activation of defense responses. At both times, enzymes involved in the synthesis and degradation of the cell wall were identified, suggesting a recycling and wall remodeling in order to stop the development of the fungus. These findings provide important information on the molecular responses of P. persica against T. deformans.