BGS 276, Grain protein content 1, gpc1

Hordeum vulgare NAC transcription factor = HvNAM-1 (3).

Monofactorial recessive (3, 12).
Located in chromosome 6HS (10, 12); gpc1.c is very close to HVM74 (an SSR marker positioned just above the endonuclease organizer region in 6HS) (10, 12); gpc1.c is in 0.7 cM interval encompassing the peak QTL for grain protein content (GPC) (3); gpc1.c is at 50.35 Mb (5)

The spring six-rowed barley Karl (CIho 15487) averaged over 2% lower in grain protein than its recurrent parent Traill (CIho 9538) (1, 14). Lines derived from complex crosses to Karl had 1 to 2% lower grain protein when grown under different nitrogen (N) fertilization levels (15). Presence of the gpc1.c allele was associated with a 1.3% reduction in grain protein (5, 12). Grain protein reduction associated with the gpc1.c allele were not observed in all environments (4). The Gpc1 locus influences whole-plant N allocation and management (6). Following similar times for floral transition at the shoot apical meristem, as determined by the presence of double ridge, anthesis occurred on average 5 days earlier for the high-GPC near-isogenic line than for the low-GPC line (7, 9). A delayed in development was observed also after anthesis (8). Developmental differences in post-anthesis flag leaf and whole-plant senescence between low- and high-GPC lines persisted under both long and short days (11).

Lower grain protein content is a spontaneous variant first reported in the cultivar Karl (CIho 15487) (1, 14). Variation in grain protein content values for Tibetan barleys was associated with the Gpc1 (HvNAM1) locus (2, 13).

The low grain protein content trait of Karl was likely obtained from Lousy (CIho 7147) (1); alleles that are associated with different grain protein levels are represented by Gpc1.a (Hap 2) in Chevron (PI 38061, CIho 1111); gpc1.b (Hap 7) in Lacey (PI 613603); gpc1.c (possibly Hap 1) Karl (CIho 15487) (5, 13); 10 haplotypes in the HvNAM1 DNA sequence from Tibetan landraces and wild barley (13).

The low grain protein content trait of Karl, gpc1.c, was likely inherited from Lousy (CIho 7147 (1); Gpc1.a in Chevron (PI 38061, CIho 1111) and Bowman (PI 483237, NGB 22812) (5, 15); gpc1.b in Lacey (PI 613603) and Rasmusson (PI 658495); gpc1.c in Karl (CIho 15487); gpc1.c in ND11231-01 (PI 643261) and Logan (PI 592784) (Weston); a recombinant between gpc1.c and Rpt5.f (Reaction to Pyrenophora teres 5 from CIho 5791) in ND Genesis (PI 677345).

1. Burger, W.C., D.M. Wesenberg, J.E. Carden, III, and P.E. Pawlisch. 1979. Protein content and composition of Karl and related barleys. Crop Sci. 19:235-238.
2. Cai, S., G. Yu, X. Chen, Y. Huang, X. Jiang, G. Zhang, and X. Jin. 2013. Grain protein content variation and its association analysis in barley. BMC Plant Biology 13:35.
3. Distelfeld, A., A. Korol, J. Dubcovsky, C. Uauy, T. Blake, and T. Fahima. 2008. Colinearity between the barley grain protein content (GPC) QTL on chromosome arm 6HS and the wheat Gpc-B1 region. Mol. Breed. 22:25-38.
4. Emebiri, L.C., D.B. Moody, R. Horsley, J. Panozzo, and B.J. Read. 2005. The genetic control of grain protein content variation in a doubled haploid population derived from a cross between Australian and North American two-rowed barley lines. J. Cereal Sci. 41:107-114.
5. Falcon, C.M., R. Horsley, G. Hu, T. Blake, and K.P. Smith. 2019. Mapping QTLs for grain protein concentration and agronomic traits under different nitrogen levels in barley. Crop Sci. 59:68-83.
6. Heidlebaugh, N.M., B.R. Trethewey, A.K. Jukanti, D.L. Parrott, J.M. Martin, and A.M. Fischer. 2008. Effects of a barley (Hordeum vulgare) chromosome 6 grain protein content locus on whole-plant nitrogen reallocation under two different fertilisation regimes. Funct. Plant Biol. 35:619-632.
7. Jukanti, A.K., and A.M. Fischer. 2008. A high-grain protein content locus on barley (Hordeum vulgare) chromosome 6 is associated with increased flag leaf proteolysis and nitrogen remobilization. Physiol. Plant. 13: 426-439.
8. Jukanti, A.K., N.M. Heidlebaugh, D.L. Parrott, I.A. Fischer, K. McInnerney, and A.M. Fischer. 2008. Comparative transcriptome profiling of near-isogenic barley (Hordeum vulgare) lines differing in the allelic state of a major grain protein content locus identifies genes with possible roles in leaf senescence and nitrogen reallocation. New Phytol. 177:333-349.
9. Lacerenza, J.A., D.L. Parrott, and A.M. Fischer. 2010. A major grain protein content locus on barley (Hordeum vulgare L.) chromosome 6 influences flowering time and sequential leaf senescence. J. Exp. Bot. 61:3137-3149.
10. Mickelson, S., D. See, F.D. Meyer, J.P. Garner, C.R. Foster, T.K. Blake, and A.M. Fischer. 2003. Mapping of QTL associated with nitrogen storage and remobilization in barley (Hordeum vulgare L.) leaves. J. Exp. Bot. 54:801-812.

J.D. Franckowiak. 2018. Barley Genet. Newsl. 48:120-121.