Insight in the molecular basis of virulence can help to identify new and more durable sources of resistance to the root-knot nematode Meloidogyne incognita in tomato. In nematode genomes, evidence of positive, diversifying selection can point to loci involved in a molecular arms race with other organisms. We used evidence of positive selection as a first criterion to identify novel virulence genes in the genome of M. incognita, one of which encodes the effector MiL648. Bioassays with M. incognita on tomato plants overexpressing an RNAi construct matching the MiL648 sequence showed that this gene is required for nematode virulence. Likewise, tomato plants overexpressing MiL648 were more susceptible to M. incognita, demonstrating that it functions as a bona fide effector. We identified six likely host targets of MiL648 in a yeast two-hybrid screen of nematode-infected roots of tomato, including the 12-oxophytodienoate reductase SlOPR2. We confirmed the interaction between SlOPR2 and MiL648 in planta by transient expression and co-immunoprecipitation in leaves of Nicotiana benthamiana. We therefore concluded that the effector MiL648 enhances the virulence of M. incognita through its interactions with SlOPR2.
|Publication status||Published - 18 Jul 2019|
|Event||IS-MPMI XVIII Congress - Scottish Event Campus, Glasgow, United Kingdom|
Duration: 14 Jul 2019 → 18 Jul 2019
|Conference||IS-MPMI XVIII Congress|
|Period||14/07/19 → 18/07/19|