GrainGenes

Coordinator's report: Disease and pest resistance genes

J. Helms Jørgensen

Plant Genetics, Building 301, Plant Biology and Biogeochemistry Department,
Risø National Laboratory, DK-4000 Roskilde, Denmark.

In BGN Vol. 22 comprehensive lists were published on 1) Genes for powdery mildew reaction in barley in conjuction with a review (Jørgensen 1994) and 2) Loci for disease and pest reaction. These lists have been updated in BGN Vol. 23, 24 and 25. Since that time the following new data have been published (to January 1997).

Recently, a powdery mildew resistance that in resistance spectrum and infection type is identical to that of gene Mlat is found present in several cultivars in the former Czeckoslovakia (Dreiseitl 1996). This gene is of unknown origin and is new for European barley breeding. Kasha et al. (1996) found that the "new" mildew resistance gene Mlhb is on a chromosome segment transfered from H. bulbosum to barley chromosome 2. This gene is a promising new source of resistance because it confers infection type 0 and is completely resistant in the field in Denmark. Three other "new" mildew resistance genes Mlf on chromosome 1L, mlt on 1S and Mlj on 7L and derived from H. spontaneum were reported by Schönfeld et al. (1996). They represent three new loci. Gene mlt was originally designated Mlb (cf. Jørgensen 1995). Recently Steffenson and Kleinhofs (1995) reported that cv. `Harrington' possesses powdery mildew resistance gene Mlg. Still another "new" mildew resistance specificity was detected by Brown et al. (1996) in the near-isogenic line P17. And Czembor and Johnston (1996) described a apparently "new" recessive mildew resistance gene in a Tunesien landrace barley. Baum et al. (1996) reported two powdery mildew resistances associated with molecular markers on chromosome 3. In a QTL study of progeny of `Blenheim' x `Line E224/3' Thomas et al. (1995) found responses to three diseases in field trials. They were probably due to mildew resistance gene Mla13, two yellow rust resistance genes of which one may be Yr4, and leaf rust resistance gene Rph12. Lastly, Freialdenhoven et al. (1996) described six mutagen-induced genes in two loci Ror1 and Ror2 (required for Mlo resistance). Previously, one of these loci was designated Nor1 (necessary for Mlo resistance) (cf. Jørgensen 1995). They reduce the level of resistance confered by the mlo resistance genes.

Two new loci for leaf rust resistance, Rph13 and Rph14, were found by Jin et al. (1996). Kicherer et al. (1996) described QTLs on chromosomes 1, 2 and 3 that affected the phenotypic variance of resistance to leaf rust. Long et al. (1995) have proposed a system of pathotype nomenclature for leaf rust based on 12 differential varieties with genes Rph1 to Rph12.

A new stem rust resistance gene was designated for the interim as RpgU by Fox and Harder (1995). Gene rpg4 was described by Harder and Legge (1996); they also suggested a probable second recessive gene derived from line Q21861. Sun et al. (1996) found a semi-dominant gene in barley that confers resistance to stem rust from rye. It cosegregates with the gene rpg4 that confers resistance to stem rust from wheat. Sun et al.s paper showed me that I have previously missed a recessive stem rust resistance gene now designated as rpgBH reported by Steffenson et al. (1984).

QTLs affecting yellow rust reaction was detected in a DH-population from `Blenheim' x `Line E224/3' (Thomas et al. 1995).

The `Steptoe' x `Morex' DH-population has been studied by Steffenson et al. (1996). They found two QTLs on chromosome 6 and one on 4 affecting seedling reaction to net blotch; further, one gene in a locus named Rcs5 on 1 that affect spot blotch. In the adult plant stage there were seven QTLs on chromosomes 1, 2, 3, 3, 4, 6 and 7 affecting net blotch and two QTLs affecting adult spot blotch reaction. The four genes previously designated hl1, hl2, hl3 and hl4 (cf. Søgaard and von Wettstein-Knowles, 1987) affecting spot blotch reaction are redesignated Rcs1 to Rcs4 by Steffenson et al. (1996). Net blotch reaction as a QTL has also been described by Graner et al. (1996) in a DH-population from the winter barley cultivars `Igri' x `Franka'. They detected a dominant gene on chromosome 3. It was tentatively designated Pt,,a because of unknown allelic relationship to another Pt gene on chromosome 3.

Another DH-population, from `Igri' x `Triton', was tested for scald reaction by Graner and Tekauz (1996). They found an Rh gene on the long arm of chromosome 3. Baum et al. (1996) report on seven QTLs for scald reaction in a SSD-population of `Tadmore' x `unnamed line'. They are on chromosomes 3 and 5.

The `Proctor' x `Nudinka' DH-population was screened for reaction to barley leaf stripe by Pecchioni et al. (1996). They found one major QTL on chromosomes 1 close to locus n and another on 2. In addition they report two minor QTLs.

The Yd2 gene conferring resistance to specific isolates of barley yellow dwarf virus is reported to be on chromosome 3 by Collins et al. (1996).

Mornhinweg et al. (1996) report that resistance to the russian wheat aphid in a barley germplasm line STARS-9301B is under control of two genes Dnb1 and Dnb2 and that of line STARS-9577B is under control of two dominant genes with recessive epistasis.

Lastly, Harrabi (1996) has briefly reviewed what has been achieved in resistance breeding to major barley pathogens (rusts excluded). Further, Boesen et al. (1996) present an update of the designations of barley and wheat powdery mildew resistance and virulence in Europe.

References:

Baum, M., H. Sayed, J.L. Arous, S. Grando, S. Ceccarelli, G. Backes, W. Mohler, A. Jahoor and G. Fischbeck, 1996. QTL analysis of agronomic important characters for dryland conditions in barley by using molecular markers. In: V International Oat Conference & VII International Barley Genetics Symposium, Proceedings (eds A. Slinkard, G. Scoles and B. Rossnagel), pp. 241-243.

Boesen, B., M.S. Hovmøller and J.Helms Jørgensen, 1996. Designation of barley and wheat powdery mildew resistance and virulence in Europe. In: Integrated control of cereal mildews and rusts: Towards coordination of research across Europe. (eds E. Limpert, M.R. Finckh and M.S. Wolfe), COST Action 817, EU, Brussels, pp. 2-9.

Brown J.K.M., S. Le Boulaire and N. Evans, 1996. Genetics of responses to morpholine-type fungicides and of avirulences in Erysiphe graminis f.sp. hordei. European Journal of Plant Pathology 102: 479-490.

Collins, N.C., N.G. Plantridge, C.M. Ford and R.H. Symons, 1996. The Yd2 gene for barley yellow dwarf virus resistance maps close to the centromere of the long arm of barley chromosome 3. Theor. Appl. Genet. (in press).

Czembor, J.H. and M.R. Johnston, 1996. Resistance genes to powdery mildew of barley in selections from Tunisian barley landraces. In: Proc. of the 9th European and Mediteranean Cereal Rusts & Powdery Mildews Conference, Lunteren, pp. 243.

Dreiseitl, A., 1996. Powdery mildew resistance of barley cultivars grown in the visegrad-group countries. In: Proc. of the 9th European and mediteranean Cereal Rusts & Powdery Mildews Conference, Lunteren, pp. 141-148.

Fox, S.L. and D.E. Harder, 1996. Resistance to stem rust in barley and inheritance of resistance to race QCC. Can. J. Plant Sci. 75: 781-788.

Freialdenhoven, A., C. Peterhänsel, J. Kurth, F. Kreuzaler and P. Schulze-Lefert, 1996. Identification of genes required for the function of non-race-specific mlo resistance to powdery mildew in barley. The Plant Cell 8: 5-14.

Graner, A. and A. Tekauz, 1996. RFLP mapping in barley of a dominant gene conferring resistance to scald (Rhynchosporium secalis). Theor. Appl. Genet. 93: 421-425.

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.

Harder, D.E. and W.G. Legge, 1996. Stem rust resistance in barley - an overview. Proc. of the 9th European and Mediterranean Cereal Rusts & Powdery Mildews Conference, Lunteren, pp. 182-185.

Harrabi, M., 1996. Breeding for resistance to the major fungal leaf pathogens of barley. In: V International Oat Conference & VII International barley Genetics Symposium, Proceedings (eds A. Slinkard, G. Scoles and B. Rossnagel), pp. 314-325.

Jin, Y., G.H. Cui, B.J. Steffenson and J.D. Franckowiak, 1996. New leaf rust resistance genes in barley and their allelic and linkage relationships with other Rph genes. Phytopathology 86: 887-890.

Jørgensen, J.H., 1994. Genetics of powdery mildew resistance in barley. Crit. Rev. Plant sci. 13, 97-119.

Jørgensen, J.H., 1995. Coordinators report. Disease and pest resistance genes. Barley Genetics Newsletter 24: 156-158.

Kasha, K.J., R.A. Pickering, H.M. William, A. Hill, R. Oro, S. Reader and J.W. Snape, 1996. GISH and RFLP facilitated identification of a barley chromosome carrying powdery mildew resistance from Hordeum bulbosum. In: V International Oat Conference & VII International Barley Genetics Symposium, Proceedings (eds A. Slinkard, G. Scoles and B. Rossnagel), pp. 338-340.

Kicherer, S., G. Backes, A. Jahoor, U. Walther and G. Fischbeck, 1996. Characterisation of a barley DH-population with regard to resistance against Puccinia hordei by means of QTL-analysis. Proc. of the 9th European and Mediterranean Cereal Rusts & Powdery Mildew Conference, Lunteren, pp. 231.

Long, D.L., B.J. Steffenson, K.J. Leonard, Y. Jin, M.E. Hughes and D.H. Casper, 1995. Barley Rusts in the United States in 1995. Barley Newsletter 39: 63-71.

Mornhinweg, D.W., D.R. Porter and J.A. Webster, 1996. Inheritance of russian wheat aphid resistance in spring barley germplasm line STARS-9577B. Barley Genetics Newsletter 25: 34-35.

Pecchioni, N., P. Faccioli, H. Toubia-Rahme, G. Valè and V. Terzi, 1996. Quantitative resistance to barley leaf stripe (Pyrenophora graminea) is dominated by one major locus. Theor. Appl. Genet. 93: 97-101.

Schönfeld, M, A. Ragni, G. Fischbeck and A. Jahoor, 1996. RFLP mapping of three new loci for resistance genes to powdery mildew (Erysiphe graminis f.sp. hordei) in barley. Theor. Appl. Genet. 93: 48-56.

Steffenson, B.J. and A. Kleinhofs, 1995. Genetics and mapping of powdery mildew resistance in the Harrington/TR306 and Harrington/Morex doubled haploid populations. Barley Newsletter 39: 89-91.

Steffenson, B.J., P.M. Hayes and A. Kleinhofs, 1996. Genetics of seedling and adult plant resistance to net blotch (Pyrenophora teres f. teres) and spot blotch (Cochliobolus sativus) in barley. Theor. Appl. Genet. 92: 552-558.

Steffenson, B.J., R.D. Wilcoxson and A.P. Roelfs, 1984. Inheritance of resistance to Puccinia graminis f.sp. secalis in barley. Plant Dis. 68: 762-763.

Sun, Y., B.J. Steffenson and Y. Jin, 1996. Genetics of resistance to Puccinia graminis f.sp. secalis in barley line Q21861. Phytopathology 86: 1299-1302.

Søgaard, B. and P. von Wettstein-Knowles, 1987. Barley: Genes and Chromosomes. Carlsberg Res. Commun. 52: 123-196.

Thomas, W.T.B., W. Powell, R. Waugh, K.J. Chalmers, U.M. Barua, P. Jack, V. Lea, B.P. Forster, J.S. Svanston, R.P. Ellis, P.R. Hanson and R.C.M. Lance, 1995. Detection of quantitative trait loci for agronomic, yield, grain and disease characters in spring barley (Hordeum vulgare L.). Theor. Appl. Genet. 91: 1037-1047.