Awn microstructural observation revealing multifunction of awn-inhibitor Gene B1 in near-isogenic lines with different awn length


  • Xingfeng Li Shandong Agricultural University



Common wheat; NILs-B1; awn length; SEM; anatomy


Awn is one of wheat morphological characteristics and acts as a highly effective organ for photosynthesis in wheat. Variation in awn length is controlled primarily by three major genes, most commonly the dominant awn suppressor Tipped1 (B1). So far, the function of B1 is not well understood. In this paper, we identified a pair of near-isogenic lines (NILs) containing different awn inhibition gene B1 alleles and observed microstructures and ultra-microstructure of their awns. The typical awns differences between the NILs represented by the cross-sectional area and chloroplasts number. Long awn line had a larger cross-sectional area, and more cells in various parts of tissues, especially the cells containing more and larger chloroplasts, which could attribute to a strong cytological basis for photosynthesis. The results may suggest that the gene has pleiotropic effects in the control development of awn tissue structure and grain yield.


Abebe T, Wise RP, Skadsen RW (2009). Comparative transcriptional profiling established the awn as the major photosynthetic organ of the barley spike while the lemma and the palea primarily protect the seed. Plant Genome 2: 247-259.
Antonyuk MZ, Prokopyk DO, Martynenko VS, Ternovska TK (2012). Identification of the genes promoting long awnness in the Triticum Aestivum/Aegilops Umbellulata introgressive line. Cytology & Genetics 46: 136-143.
Blum A. (1985) Photosynthesis and transpiration in leaves and ears of wheat and barley varieties. Journal of Experimental Botany 36: 432-440.
Cuthbert JL, Somers D J, Brûlé-Babel A L, Brown PD, Crow GH. (2008) Molecular mapping of quantitative trait loci for yield and yield components in spring wheat (Triticum aestivum L.). Theoretical & Applied Genetics. 117: 595-608.
Das NR, Mukherjee NN (1991). Grain yield contribution by leaf and awn in dwarf wheat (Triticum aestivum L.) after rice (Oryza sativa L.). Environment and Ecology 9: 33-36.
DeWitt N, Guedira M, Lauer E, Sarinelli M, Tyagi P, Fu DL, Hao QQ, Murphy JP, Marshall D, Akhunova A, Jordan, K, Akhunov E, Brown-Guedira G (2020). Sequence-based mapping identifies a candidate transcription repressor underlying awn suppression at the B1 locus in wheat. New Phytologist 225(1): 326-339.
Du B, Cui F, Wang HG, Li XF. (2010) Characterization and Genetic Analysis of Near-isogenic Lines of CommonWheat for Awn-inhibitor Gene B1. Molecular Plant Breeding 8(2): 259-264.
Elbaum R, Zaltzma L, Burgert I, Fratzl P. (2007) The Role of Wheat Awns in the Seed Dispersal Unit. Science 316: 884-886.
Elshire RJ, Glaubitz JC, Sun Q, Poland JA, Kawamoto K, Buckler ES, Mitchell SE. (2011) A robust, simple genotyping-by-sequencing (GBS) approach for high diversity species. PLoS ONE 6: e19379
Evans LT, Bingham J, Jackson P, Sutherland J. (1972) Effect of awns and drought on the supply of photosynthate and its distribution within wheat ears. Annals of Applied Biology (70): 67-76.
Evans LT, Rawson HM (1970) Photosynthesis and Respiration by the Flag Leaf and Components of the Ear During Grain Development In Wheat. Australian Journal of Biological Sciences 23: 245-254.
Grundbacher FJ. (1963) The physiological function of the cereal awn. Botanical Review 29(3): 366-381.
Huang D, Zheng Q, Melchkart T, Bekkaoui Y, Konkin D J, Kagale S, Martucci M, You FM, Clarke M, Adamski NM, Chinoy C, Steed A, McCartney CA, Cutler AJ, Nicholson P, Feurtado JA (2020). Dominant inhibition of awn development by a putative zinc-finger transcriptional repressor expressed at the B1 locus in wheat. New Phytologist 225(1): 340-355.
Jin D, Wang DZ, WanX, Li R Z, Chen S L, Yang W L, Zhang AM, Liu DC, Zhan KH. (2019) Fine mapping and candidate gene analysis of awn inhibiting gene B2 in common wheat. Acta Agronomica Sinica, 45(6): 807-817.
Khaliq I, Irshad A, Ahsan M. (2008) Awns and flag leaf contribution towards grain yield in spring wheat (Triticum aestivum L.). Cereal Research Communications 36: 65-76.
Li XJ, Wang HG, Li HB, Zhang LY, Teng NJ, Lin QQ, Wang JA, Kuang TY, Li ZS, Li B, Zhang AM, Lin JX. (2006) Awns play a dominant role in carbohydrate production during the grain-filling stages in wheat (Triticum aestivum). Physiologia Plantarum, 127: 701-709.
Liu C, Yang ZJ, Feng J, Zhou JP, Chi SH, Ren ZL. (2006) Development of Dasypyrum genome specific marker by using wheat microsatellites, Yichuan (Hereditas) 28(12): 1573-1579.
Mackay IJ, Bansept-Basler P, Barber T, Bentley AR, Cockram J, Gosman N, Greenland AJ, Horsnell R, Howells R, O’Sullivan DM, Rose GA, Howell PJ. (2014) An eight-parent multiparent advanced generation inter-cross population for winter-sown wheat: creation, properties, and validation. G3: Genes Genomes Genetics 4: 1603-1610.
Motzo R, Giunta F. (2002) Long awnness affects grain yield and kernel weight in near-isogenic lines of durum wheat. Australian Journal of Agricultural Research 53: 1285-1293.
Olughemi LB. (1978). Distribution of carbon-14 assimilated by wheat awns. Annals of Applied Biology 9: 111-114.
Olughemi LB, Bingham J, Austinm RB. (1976) Ear and flag leaf photosynthesis of long awn and short awn Triticum species. Annals of Applied. Biology 84: 231-240.
Paillard S, Schnurbusch T, Winzeler M, Messmer M, Sourdille P, Abderhalden O, Keller B, Schachermayr G. (2003) An integrative genetic linkage map of winter wheat (Triticum aestivum L.). Theoretical and Applied Genetics 107: 1235-1242.
Qureshi N, Bariana H S, Zhang P, McIntosh R, Bansal UK, Wong D, Hayden MJ, Dubcovsky J, Shankar M (2018) Genetic relationship of stripe rust resistance genes Yr34 and Yr48 in wheat and identification of linked KASP markers. Plant Disease 102: 413-420.
Rebetzke GJ, Bonnett D, Reynolds MP (2016) Awns reduce grain number to increase grain size and harvestable yield in irrigated and rainfed spring wheat. Journal of Experimental Botany 67: 2573-2586.
Somers DJ, Isaac P, Edwards K. (2004) A high-density wheat microsatellite consensus map for bread wheat (Triticum aestivum L.), Theoretical and Applied Genetics 109: 1105-1114.
Sourdille P, Singh S, Cadalen T, Brownguedira GL, Qi LL, Gill BS, Dufour P, Murigneux A, Bernard M. (2004) Microsatellite-based deletion bin system for the establishment of genetic-physical map relationships in wheat (Triticum aestivum L.). Functional & Integrative Genomics 4: 12-25.
Teare ID, Sly JW, Waldren RP, Goltz SM. (1972) Comparative data on the rate of photosynthesis, respiration and transpiration different organs in long awn and short awn isogenic lines of wheat. Canadian Journal of Plant Science 52: 965-971.
Wang DZ, Yu K, Sun LJ, Chu JF, Wu JC, Xin PY, Edita Gregová, Li X, Sun JZ, Yang WL, Zhan KH, Zhang AM, Liu DC (2020) Natural variation in the promoter of Awn Length Inhibitor 1 (ALI-1) is associated with awn elongation and grain length in common wheat. The Plant Journal DOI:10.1111/tpj.14575.
Wang Z, Gu YJ, and Gao YZ. (1993) Structure and photosynthetic characteristics of awns of wheat and barley. Journal of Integrative Plant Biolog 35(12): 921-928.
Watkins AE, Ellerton S (1940) Variation and genetics of the awn in Triticum. Journal Genetics 40: 243-270.
Yoshioka M, Iehisa JCM, Ohno R, Kimura T, Enoki H, Nishimura S, Nasuda S, Takumi S. (2017) Three dominant short awn genes in common wheat: fine mapping, interaction and contribution to diversity in awn shape and length. PLoS One 12: e0176148.
Yuo T, Yamashita Y, Kanamori H, Matsumoto T, Lundqvist U, Sato K, Ichii M, Jobling S A, Taketa S. A (2012) SHORT INTERNODES (SHI) family transcription factor gene regulates awn elongation and pistil morphology in barley. Journal Experimental Botany 63: 5223-5232.




How to Cite

Li, X. (2021). Awn microstructural observation revealing multifunction of awn-inhibitor Gene B1 in near-isogenic lines with different awn length. Caryologia. International Journal of Cytology, Cytosystematics and Cytogenetics.