BGS 667, Reaction to Pyrenophora teres 1, Rpt1

Resistance to Pyrenophora teres = Pt in Tifang (12).
Resistance to Pyrenophora teres 1 = Pt1 in Tifang (9, 12).
Resistance to Pyrenophora teres 1a = Rpt1a in Tifang (3).
Resistance to Pyrenophora teres a = Pt,,a (5).
QTL for resistance to Pyrenophora teres f. teres seedling 3HL = QRpts3L (11).
QTL for resistance to NFNB seedling Alexis/Sloop 3H = QNFNBSLR.Al/S-3H (7).

Monofactorial incomplete dominant (3, 6, 9, 12); two complementary genes in Harbin to some isolates (2).
Located in chromosome 3HL (3); Rpt1.a is associated with chromosome 3H based on trisomic analysis (3); Pt,,a from Igri mapped in 3HL about 0.8 cM distal from RFLP marker cMWG680 (5); several QTL from other cultivars mapped in the proximal region of 3HL (7, 11); near microsatellite marker Bmag606 (7); near microsatellite marker Bmag225 (11).

Moseman (10) recommended the assignment of a three letter code to disease reaction loci in barley with R as the first letter and the genus and species name of the causal organism as the second and three letters. The seedling reactions of cultivars with the Rpt1.a (Pt1) gene to Pyrenophora teres f. teres (Ptt) isolates were measured as 1 on a scale where 0 = very resistant and 4 = susceptible; however, some Ptt isolates produced susceptible reactions in the accessions tested (3). Heterozygous individuals showed intermediate reactions ranging from 1 to 3 (2, 3, 6, 11). Based on a low frequency of susceptible plants in crosses among resistant accessions, Mode and Schaller (9) reported Tifang as having Pt1, but a closely linked gene (Pt2) was present in Manchurian, Ming, Harbin Canadian Lake Shore and CIho 4922. An unlinked gene (Pt3) was also present in CIho 4922 (9). Khan and Boyd (6) concluded that CIho 5791 and CIho 9819 have one the resistance gene of (Pta), which is not Pt1, Pt2, or Pt3 as described by Mode and Schaller (9). The Pt1 and Pt2 genes were assumed to be alleles (6). Bockelman et al. (3) could not differentiate the linked genes in chromosome 3H using trisomic stocks of Betzes and associated only one resistance factor with chromosome 3H, Rpt1a. Genes for resistance to various isolates of Ptt from several cultivars have been mapped in chromosome 3HL (5, 7, 11). The differences among these reports have not been resolved (8), but Tifang is still classified as having the Rpt1.a gene. The presence of additional Rpt genes in Tifang is possible because it conferred a resistant response to a large number of California isolates of Ptt (13). When testing Ptt isolates from around the world, Tifang and Harbin were demonstrated effective to confer effective resistance to many Ptt isolates in many countries (1, 4).

Natural occurrence in Tifang (PI 69426, CIho 14373, CIho 4407-1) collected from Heilongjiang Province in China (3); the same resistance gene may be present in Canadian Lake Shore (CIho 2758, PI 20819), CIho 4922 (PI 73737), Harbin (CIho 4929, PI 72745), Manchuria (CIho 2330), and Ming (CIho 4797, PI 70854) (6, 9).

Rpt1.a in Tifang (PI 69426, CIho 14373) collected from Heilongjiang Province in China (3, 10, 12); Rpt1.a in Harbin (CIho 4929, PI 72745) (6, 9); Rpt1.b in CIho 9819 (PI 195985) from Ethiopia (3); possible alleles are present in Igri (PI 428488) (6), Alexis (PI 564487) (7, 11), and Arapiles (PI 591926) (11).

Rpt1.a in Tifang (PI 69426, CIho 14373), Rpt1.a in Harbin (CIho 4929, PI 72745).

1. Afanasenko, O.S., M. Jalli, H.O. Pinnschmidt, O. Filatova, and G.J. Platz. 2009. Development of an international standard set of barley differential genotypes for Pyrenophora teres f. teres. Plant Pathol. 58:665-676.

2. Afanasenko, O., N. Mironenko, O. Filatova, D. Kopahnke, I. Krämer, and F Ordon. 2007. Genetics of host-pathogen interactions in the Pyrenophora teres f. teres (net form) – barley (Hordeum vulgare) pathosystem. Eur. J. Plant Pathol. 117:267-280.

3. Bockelman, H.E., E.L. Sharp, and R.F. Eslick. 1977. Trisomic analysis of genes for resistance to scald and net blotch in several barley cultivars. Can. J. Bot. 55:2142-2148.

4. Boungab, K., L. Belabid, Z. Fortas, and B. Bayaa. 2012. Pathotype diversity among Algerian isolates of Pyrenophora teres f. teres. Phytopathologia Mediterranea 51:577-586.

5. Graner, A., B. Foroughi-Wehr, and A. Tekauz. 1996. RFLP mapping of a gene in barley conferring resistance to net blotch (Pyrenophora teres). Euphytica 91:229-234.

6. Khan, T.N., and W.J.R. Boyd. 1969. Inheritance of resistance to net blotch in barley II. Genes conditioning resistance against race W.A.-2. Can. J. Genet. Cytol. 11:592-597.

7. Lehmensiek, A., G.J. Platz, E. Mace, D. Poulsen, and M.W. Sutherland. 2007. Mapping of adult plant resistance to net form of net blotch in three Australian barley populations. Aust. J. Agric. Res. 58:1191-1197.

8. Liu, Z., S.R. Ellwood, R.P. Oliver, and T.L. Friesen. 2011. Pyrenophora teres: profile of an increasingly damaging barley pathogen. Mol. Plant Pathol. 12:1-19.

9. Mode, C.J., and C.S. Schaller. 1958. Two additional factors for resistance to net blotch in barley. Agron. J. 50:15-18.

10. Moseman, J.G. 1972. Report on genes for resistance to pests. Barley Genet. Newsl. 2:145-147.

11. Raman, H., G.J. Platz, K.J. Chalmers, R. Raman, B.J. Read, A.R. Barr, and D.B. Moody. 2003. Mapping of genomic regions associated with net form of net blotch resistance in barley. Aust. J. Agric. Res. 54:1359-1367.

12. Schaller, C.W. 1955. Inheritance of resistance to net blotch of barley. Phytopathology 48:477-480.

13. Steffenson, B.J., and R.K. Webster. 1992. Pathotype diversity of Pyrenophora teres f. teres on barley. Phytopathology 82: 170-177.

J.D. Franckowiak 2012. Barley Genet. Newsl. 42:750.

J.D. Franckowiak and G.J. Platz. 2013. Barley Genet. Newsl. 43:177-178.