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Application of Host-Induced Gene Silencing (HIGS) for control of rice blast disease

Mengying Wang: NCSU

<div>Rice blast, caused by the hemibiotrophic fungus<em> Magnaporthe oryzae,</em> is the most destructive disease of rice world-wide. As an alternative to readily broken-down disease resistance, HIGS (host induced gene silencing) is being developed as a strategy to create a new type of disease resistant plants. Eight genes (<em>CRZ1, Pmc1, MagB, Lhs1, CYP51A, CYP51B, Exo70, Sec5</em>) that play important roles in pathogenicity and development of <em>M. oryzae</em> were chosen for HIGS. HIGS vectors were transformed into rice calli through the <em>Agrobacterium</em>-mediated method. T0, T1 and T2 generations of transgenic rice plants were generated and the insertion of HIGS fragments confirmed. HIGS transgenic rice plants challenged with <em>M. oryzae</em> showed significantly reduced disease compared with non-silenced control plants. <span>Following infection with <em>M. oryzae</em> </span>of HIGS transgenic plants, expression levels of target genes <em></em>were reduced as demonstrated by Quantitive RT-PCR. In addition, treating <em>M. oryzae</em> with naked diced siRNA derived from the target genes silenced their expression in the fungus and caused functional collapse. These findings suggest RNA silencing signals can be transferred from host to invasive fungus and HIGS has potential to generate resistant rice against <em>M. oryzae</em>.</div>