Transmission of Phloem-Limited Viruses to the Host Plants by Their Aphid Vectors

Abstract

Plant viruses produce important economic losses in crops worldwide. The study of their transmission by insects has been key in order to develop new strategies to interfere with their spread. Studies on the monitoring of aphid probing behavior by using the electrical penetration graph (EPG) technique allowed to study the different aphid stylet activities in plant tissues associated with the transmission of plant viruses. Aphids produce intermittent intracellular punctures (commonly named as “potential drops”: pds) along the stylet pathway, ultimately reaching the phloem tissues. The phloem-pd has been recently described as the key stylet activity in plant cells associated with the transmission of phloem-limited viruses by aphids. This behavioral pattern represents the first report of a brief intracellular puncture produced by aphids in phloem tissues associated to the transmission of a phloem-limited virus. A single brief phloem-pd (3–5 s) was mandatory to transmit both semipersistently and persistently transmitted, phloem-limited viruses by aphids. Stylet penetration of both sieve elements and companion cells of the host plant during the occurrence of the phloem-pd by M. persicae were confirmed by using confocal laser-scanning microscopy together with CT-microtomography. In this chapter, we revisit the main approaches recently carried out in the field of aphid probing and feeding behavior in association with the transmission of phloem-limited viruses transmitted in either a semipersistent or persistent manner.