TRANSCRIPTOME ANALYSIS OF PEACH-TAPHRINA DEFORMANS INTERACTION IN A SUSCEPTIBLE GENOTYPE

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

Salta

Congreso; LIVI Congreso de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2019

Prunuspersica (L) Batsch, is a tree of great economic importance and is susceptibleto numerous diseases including the Peach Leaf Curl?a widely worldwidedistributed disease that generates losses ranging between 2.5 and 3 milliondollars per year. The causal agent of the disease is the dimorphic fungusTaphrina deformans. The pathogen invades new shoots in early spring when theleaves are young and have a thin cuticle. The symptoms include chlorosis, pinkpigmentation, the characteristic curling of the leaf, and ultimately thesenescence of the leaves and the tree?s death. Normally, the disease iscontrolled with agrochemicals, but its high cost, its potential negative impacton animals and humans, and itsinsufficient control have increased the demandfor farming practices that reduce risks to health and the environment, beingnecessary 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 werecollected at 0, 12, and 96 h post-inoculation (hpi) and used for RNAextraction. RNAseq analysis was conducted to unravel the early responses of thehost. The analysis yielded357 and 210 differentially expressed genes (DEGs) at12 and 96 hpi compared to 0 hpi, respectively. Approximately 43% of the DEGswere induced and 57% were repressed in both comparisons. The most representedfunctional categories were RNA, signaling, hormones, proteins and bioticstress. Regarding RNA, transcription factors (FT) such as WRKY, bHLH, HB, MYB,and zinc fingers FT were differentially expressed. While MYB FTs were inducedboth at 12 and 96 hpi, bHLH FTs were exclusively up-regulated at 12 hpi.Differences regarding phytohormones were also found; enzymes involved in theethylene 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 metabolismof brassinosteroids was induced at 96 hpi. The increase in these hormonessynthesis upon infection could activate defense responses. On the contrary, theabscisic acid biosynthetic pathway was repressed as an early response. Theinduction of auxin-responsive genes was also detected and could be responsiblefor some symptoms of the disease. Furthermore, many pathogenesis-relatedproteins (PR), like Thaumatin-like proteins (PR5), Kunitz proteinase inhibitors(PR6), lipid transfer proteins (PR14), B-1,3-glucanases (PR2), andendochitinases (PR3) were induced exclusively at 12 hpi indicating theactivation of defense responses. At both times, enzymes involved in thesynthesis and degradation of the cell wall were identified, suggesting arecycling 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.