Characterization of the salivary effectors involved in the host plant adaptation of pea aphidsCharacterization of the salivary effectors involved in the host plant adaptation of pea aphids
- Date: Dec 1, 2021
- Time: 02:00 PM (Local Time Germany)
- Speaker: Po-Yuan Shih
- Institute for Genetics, Environment and Plant Protection, Ecology and Genetics of Insects, INRA, Rennes, France
- Location: Hybrid lecture (online via zoom & MPI-CE, A1.009 + A1.011)
Aphids are crop pests, which suck plant nutrients and transmit viral
diseases. During phloem feeding, many salivary proteins are secreted
into plants and function like effectors of microbial pathogens. The pea
aphid, Acyrthosiphon pisum, encompasses several biotypes each
specialized to a few plant species, but the mechanism of the host plant
specialization is unclear. Previous genetic and transcriptomic studies
of different pea aphid biotypes strongly suggest the involvement of
salivary effectors in the determination of the plant specificity. Our
recent results found that co-infestation of the pea-adapted biotype
enhanced both survival and fecundity of alfalfa-adapted biotype on pea
which is not a host of the alfalfa biotype. The electrical penetration
graph analysis further demonstrated that the alfalfa biotype showed
longer salivation and shorter phloem ingestion on pea compared with the
pea biotype. However, the duration of phloem ingestion on pea was
significantly extended in the alfalfa biotype co-infested with the pea
biotype. These results suggested that pea biotype-specific factors can
induce pea susceptibility to the pea non-adapted biotype. In order to
evaluate whether salivary effectors are involved in the aphid adaption
to pea plants, we selected several salivary effector candidates which
are highly expressed in the pea biotype relative to the alfalfa biotype,
and then characterized their effect on aphid fitness by transiently
expressing these genes in pea. One of the candidates, Ap30, was found to
enhance fecundity of pea biotype and several Ap30-interacting pea
proteins were identified by a yeast-two hybrid screening, some of them
potentially regulating plant immunity. In conclusion, our results
support the hypothesis that biotype-specific salivary effectors may be
involved in the aphid adaption to specific host plants by inducing the
host susceptibility.