Genetic analysis of lethal tip necrosis induced by Clover yellow vein virus infection in pea

Abstract

Clover yellow vein virus (ClYVV) elicits lethal tip necrosis in the pea line PI 118501. Pea line PI 118501 develops necrotic lesions and veinal necrosis on inoculated leaves, followed by systemic necrosis, leading to plant death. To understand the genetic basis of this lethal tip necrosis, we crossed lines PI 226564 and PI 250438, which develop mosaic symptoms in response to ClYVV inoculation. In reciprocal crosses of PI 118501 with PI 226564, all F 1 plants had mosaic symptoms with slight stem necrosis and early yellowing of upper leaves. Essentially the same symptom was manifested in PI 118501 × PI 250438 F 1 plants. In F 2 populations from the cross between PI 118501 and PI 226564, the observed ratios of necrosis, mosaic with slight stem necrosis, and mosaic fi t the expected 1 : 2 : 1 ratio. These results indicate that a single incompletely dominant gene confers the induction of necrosis in PI 118501. This locus in pea, conferring necrosis induction to ClYVV infection, was designated Cyn1 (Clover yellow vein virus-induced necrosis). A linkage analysis using 100 recombinant inbred lines derived from a cross of PI 118501 and PI 226564 demonstrated that Cyn1 was located 7.5 cM from the SSR marker AD174 on linkage group III.

P3N-PIPO, a Frameshift Product from the P3 Gene, Pleiotropically Determines the Virulence of Clover Yellow Vein Virus in both Resistant and Susceptible Peas

“…The GenBank/ENA/DDBJ accession number for the full-length ORF sequence of Cl-I89-1 is LC096082. (20,21). These chimeric viruses were based on Cl-No.30 infectious cDNA that we previously constructed and developed for use as a gene expression vector (7,23,37,38).…”

“…We constructed a WClMV vector that expresses P3N-PIPO from the BYMV CS strain (BY-CS), designated WCl/P3N-PIPO-CS, in order to rule out the possibility that cell death was nonspecifically caused by the overexpression of P3N-PIPO. We expected that P3N-PIPO of BY-CS would not induce cell death because BY-CS has never been reported to induce cell death in pea, including PI 226564 (20,21). Like ClYVV, however, BY-CS is a member of the genus Potyvirus, and the two viruses are closely related (39).…”

“…Extremely high virulence of ClYVV has been observed for many pea cultivars: ClYVV systemically induces cell death, resulting in plant death within 2 weeks when used to infect young plants (20)(21)(22) (Table 1). We previously reported that cell death induced by Cl-No.30 in pea cultivar PI 118501 is a form of an HR-like response accompanied by the activation of the salicylic acid (SA) pathway, which is one of the hallmarks of an HR (20).…”

“…However, Cl-No.30 infection is not localized and induces cell death systemically. A genetic study in pea suggested that this cell death is controlled by a single dominant locus called Cyn1 (21). Cyn1 has been suggested to be an NB-LRR gene whose product recognizes ClNo.…”

“…Cyn1 has been suggested to be an NB-LRR gene whose product recognizes ClNo. 30 and induces an HR associated with cell death (20,21).…”