Inheritance of Resistance to a Lentil Strain of Pea Seed-Borne Mosaic Virus in Pisum sativum

Abstract

In Pisum sativum, two independently inherited single recessive genes were found to confer resistance to the same pathotype of pea seed-borne mosaic virus from lentil (PSbMV-L1). The gene sbm-2, present in the domestic cuttivar Bonneville, was determined to be closely linked to mo, which conditions resistance to bean yellow mosaic virus and watermelon mosaic virus 2 and is known to be located In Pisum linkage group 2. The second gene, sbm-3, was found in PI 347492, a bean yellow mosaic virus-susceptible line from India, and apparently is located in a different linkage group. Both genes, independently of each other, confer resistance to PSbMV-L1, but whether they are repetitive entities remains to be determined. Pea seed-borne mosaic virus (PSbMV) was characterized by Musil in Czechoslovakia and by Inouye in Japan. 1518 In 1968, this virus was found in the United States, 917-22 and since then, its presence has been ascertained in several other countries. 13 In searching for sources of resistance to PSbMV, Stevenson and Hagedorn, Baggett and Hampton, and Hampton and Braverman screened hundreds of accessions of Pisum sativum L. with the standard strain (PSbMV-ST) and found resistant germ plasm among foreign introductions. 312-23 Hagedorn and Gritton determined that, in PI 193586 and PI 193835 accessions from Ethiopia, resistance was conferred by a single recessive gene (sftm). 8 Recently, Goodell and Hampton and Ashby et al reported that PSbMV isolates from lentils (PSbMV-L) and from New Zealand peas (PSbMV-NZ) were unable to infect pea cultivars possessing mo, the gene for resistance to bean yellow mosaic virus (BYMV). 26-24 Alconero et al demonstrated that resistance to PSbMV-Pl and PSbMV-P4 (from pea), and to PSbMV-Ll (from lentil), was pathotype specific. 1 Consequently, it appears that in P. sativum, there are distinct genetic entities for resistance to PSbMV, with each factor capable of controlling only a specific pathotype of the virus. Alone or in combination, these resistance factors were found in a number of plant introductions (Pis), mostly from. India and Ethiopia. 1 '"

Recessive Resistance in Pisum sativum and Potyvirus Pathotype Resolved in a Gene-for-Cistron Correspondence between Host and Virus

“…The P. sativum lines that have been used to differentiate the PSbMV pathotypes are of four categories: (A) susceptible to P-1, P-2, and P-4 (all-susceptible); (B) resistant to P-1, P-2, and P-4 (multiresistant); (C) resistant to P-2; and (D) resistant to P-1 and P-2 (25). Resistances to all three pathotypes of PSbMV in P. sativum are inherited as single recessive genes, designated sbm-1, sbm-2, sbm-3, and sbm-4 (26,27). The sbm genes were mapped to linkage groups II (sbm-2) and VI (sbm-1, sbm-3, and sbm-4) as part of two clusters of recessive resistance genes affecting several potyviruses (29,38).…”

“…The sbm genes were mapped to linkage groups II (sbm-2) and VI (sbm-1, sbm-3, and sbm-4) as part of two clusters of recessive resistance genes affecting several potyviruses (29,38). Resistance gene sbm-2 was mapped in category C P. sativum cultivar Bonneville (26), which is resistant to P-2 and susceptible to both P-1 and P-4 (1). Gene sbm-1 was mapped in multiresistant category B line PI 193586 (11) and later was shown to cosegregate with sbm-3 and sbm-4 (29).…”

“…Gene sbm-1 was mapped in multiresistant category B line PI 193586 (11) and later was shown to cosegregate with sbm-3 and sbm-4 (29). Resistance genes sbm-3 and sbm-4 were both defined in category B line PI 347492 as conferring resistance to P-2 and P-4, respectively (26,27). A P. sativum category D line, PI 269818, which is resistant to pathotype P-1 and P-2 but susceptible to pathotype P-4 (1), was used to map the P-1/P-4 differentiating host-specific pathogenicity determinant to the VPg cistron (15).…”

Inheritance of Resistance to a Third Pathotype of Pea Seed-Borne Mosaic Virus in Pisum sativum

“…S£ Prowidenti and Alconero also determined that sbm-2 and sbm-3 condition resistance to the same pathotype PSBMV-L1, but they are inherited independently of each other and might be duplicate entities. 6 No information is presently available regarding the linkage group of sbm-3. The frequent association of sbm-4 with sbm-1 and sbm-3 in a number of pea lines from India and Ethiopia suggests linkage.…”

“…1 This cultivar is known to be resistant to several viruses, including PSbMV-Ll and bean yellow mosaic virus (BYMV). 6 Inoculum was prepared by grinding infected pea leaves with a phosphate buffer (K + ) at pH 8.5. Test plants, previously dusted with 400-mesh Carborundum, were mechanically inoculated by rubbing the first and second fully expanded leaves.…”