Association of TaEXPB23 gene expression with coleoptile growth, seed size and plant height in water-stressed wheat

Articles in Press

Document Type : Original Article

Authors

1 Ph.D. Student, Plant Breeding and Biotechnology Department, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran

2 Associate Professor, Plant Breeding and Biotechnology Department, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran

3 Assistant Professor, Plant Breeding and Biotechnology Department, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran

4 Associate Professor, Agronomy and Plant Breeding Department, Lorestan University, Khorramabad, Iran

5 Assistant Professor, Horticulture Crops Research Department, Golestan Agricultural and Natural Resources Research and Education Center, AREEO, Gorgan, Iran

Abstract

Introduction
Changes in the size and growth rate of plant cells and tissues, driven by alterations in the expression of growth-related genes, represent one of the primary adaptive responses of plants to environmental stresses. Among these genes, TaEXPB23, a member of the expansin family, plays a key role in cell wall loosening and cell expansion, thereby promoting coleoptile elongation and early seedling growth. A longer coleoptile facilitates deeper sowing, improves seedling emergence, and enhances plant establishment under water-limited conditions, making it an important trait for drought adaptation. Although the biological function of TaEXPB23 has been reported, its association with drought tolerance and related agronomic traits in wheat, particularly in Iranian cultivars, remains poorly understood. Therefore, this study aimed to investigate the expression pattern of the TaEXPB23 gene in different wheat genotypes and to evaluate its relationship with coleoptile length, kernel weight, plant height, and drought tolerance, providing insights into its potential application in wheat breeding programs.
 
Materials and methods
The expression pattern of the TaEXPB23 gene was investigated in eight bread wheat cultivars, including Arta, Uroum, Baharan, Weebill 264, Chamran, Roshan, Hirmand, and Darya. These genotypes were selected based on their contrasting responses to drought stress, coleoptile length, and grain yield. Field experiments were conducted at the Lorestan Agricultural Research Station using a randomized complete block design with three replications under two irrigation regimes: well-watered (control) and terminal drought stress. In the drought treatment, irrigation was applied only at seedling emergence, whereas the control plots received normal irrigation throughout the growing season. Grain yield, plant height, thousand-kernel weight, coleoptile length, and coleoptile dry weight were measured. The Stress Tolerance Index (STI) was calculated to evaluate genotype responses to drought stress. For gene expression analysis, seeds were germinated under laboratory conditions, and coleoptile samples were collected at 6, 24, 48, and 72 h after germination. Total RNA was extracted using a standard protocol, and its quantity and quality were assessed by spectrophotometry and agarose gel electrophoresis, respectively. First-strand cDNA was synthesized and used for quantitative real-time PCR (RT-qPCR) with SYBR Green chemistry on a Bio-Rad iQ5 system. The 18S rRNA gene served as the internal reference. All reactions were performed in three technical replicates. Relative gene expression was quantified using the Pfaffl method and analyzed with the REST software.
 
Results and discussion
The highest average coleoptile length belonged to genotypes Roshan, Baharan, Hirmand, Oroum and Darya and the lowest to Weebille264, Chamran and Arta. The 1000 kernel weight of the eight studied genotypes was between 35.1 to 44.0 grams and the range of changes in their plant height in non-stressed conditions was between 87.8 and 110.7 cm. The expression profile of the TaEXPB23 gene differed among the wheat cultivars at 6, 24, 48, and 72 h after germination. Relative gene expression increased in almost all genotypes up to 48 hours after germination, and the closer the seedling is to the end of its coleoptile growth period (72 hours), the gene expression decreased. The existence of a negative correlation between coleoptile growth and gene expression at 6 hours and turning it into a positive correlation at 72 hours, shows that although in the early hours after germination, the increase in the expression of the TaEXPB23 caused a decrease in coleoptile growth, but with the passage of time, the changes in gene expression caused an increase in the length and dry weight of coleoptiles of wheat genotypes
 
Conclusion
Based on the correlation coefficients of gene expression with morphological traits, seed yield and tolerance indices, it can be stated that early growth and better seedling establishment as a result of higher expression of the TaEXPB23 has led to increased growth and production in mature plants, especially under drought stress.

Keywords

Main Subjects

References

Ahmed, K., Shabbir, G., Ahmed, M., 2025. Exploring drought tolerance for germination traits of diverse wheat genotypes at seedling stage: a multivariate analysis approach. BMC Plant Biology. 25, 390. https://doi.org/10.1186/s12870-025-06345-9
Aligholizadeh-Moghaddam, P., Ranjbar, G.A., Shahbazi, H., Najafi-Zarrini, H., 2020. The effect of drought stress on the expression of genes TaMOR, TaNAC69-1 and TaEXPB23 in different bread wheat (Triticum aestivum L.) cultivars. Iranian Journal of Genetics and Plant Breeding, 9, 72-82. https://doi.org/10.30479/ijgpb.2021.15069.1297
Aydin, N., Sönmez, M.E., Güleç, T., 2025. High-throughput phenotyping of wheat root angle and coleoptile length at different temperatures using 3D-printed equipment. BMC Plant Biology. 25, 112. https://doi.org/10.1186/s12870-025-06120-w
Barnabas, B., Jager, K., Feher, A., 2008. The effect of drought and heat stress on reproductive processes in cereals. Plant, Cell & Environment. 31, 11-38. https://doi.org/10.1111/j.1365-3040.2007.01727.x
Cosgrove, D.J., 2021. Expanding wheat yields with expansin. New Phytologist. 230(2), 403-405. https://doi.org/10.1111/nph.17245
Darvishnia, F., Pahlevani, M., Zaynali Nezhad, K., Azizi, K., Bagherikia, S., 2020. Graphical analysis of reaction of bread wheat genotypes to water stress in Lorestan Province. Plant Genetic Research. 7,1-18. [In Persian with English summary]. http://pgr.lu.ac.ir/article-1-172-fa.html
Darvishnia, F., 2020. Association of seed vigor and expression of gene involved in coleoptile growth with morphological traits and grain yield of wheat under rainfed conditions, PhD Thesis at Gorgan University of Agricultural Sciences and Natural Resources, 176p. [In Persian].
Darvishnia, F., Pahlevani, M., Zaynali Nezhad, K., Azizi, K., 2020. Analysis of grain yield and its attributes in bread wheat and their associations with coleoptile length under water deficit conditions, Environmental Stresses in Crop Sciences. 13, 41-56. [In Persian with English summary]. https://doi.org/10.22077/escs.2019.1893.1457
Donaldson, E., Schillinger, W.E., Dofing, S.M., 2001. Straw production and grain yield relationship in winter wheat. Crop Science. 41, 100-106. https://doi.org/10.2135/cropsci2001.411100x
Farhad, M., Hakim, M.A., Alam, M.A., Barma, N.C.D., 2014. Screening wheat genotypes for coleoptile length: A trait for drought tolerance. American Journal of Agriculture and Forestry. 2(6), 237-245. https://doi.org/10.11648/j.ajaf.20140206.11
Feng, H., Li, S., Xue, L., An, L., Wang, X., 2007. The interactive effects of enhanced UV-B radiation and soil drought on spring wheat. South African Journal of Botany. 73,429-434.
https://doi.org/10.1016/j.sajb.2007.03.008
Fernandez, G.C.J., 1992. Effective selection criteria for assessing plant stress tolerance. p. 257–270. In C. G. Kuo (Ed.), Proceedings of the International Symposium on Adaptation of Vegetables and Other Food Crops in Temperature and Water Stress. Asian Vegetable Research and Development Center, Shanhua, Taiwan. https://doi.org/10.22001/WVC.72511
Fiering, S., White Low, E., Martin, D.I., 2000. To be active or not to be active: the stochastic nature of enhancer action. Bioassays. 22, 381-38.  https://doi.org/10.1002/(sici)1521-1878(200004)22:4%3C381::aid-bies8%3E3.0.co;2-e
Fukuda, H., 2014. Plant Cell Wall Patterning and Cell Shape, Wiley Blackwell. New Jersey, USA.
García-Coronado, H., Ojeda-Contreras, A.-J., Berumen-Varela, G., Robles-Parra, J.-M., Handa, A. K., Tiznado-Hernández, M.-E., 2025. Engineering crops for enhanced drought stress tolerance: A strategy for sustainable agriculture. Agronomy. 15(8), 1912. https://doi.org/10.3390/agronomy15081912
Gholami, H., Abdolshahi, R., Mohayeji, M., Esmaeilizadeh-Moghadam, M., 2023. Investigation of coleoptile and mesocotyl as the most important factors for the establishment of bread wheat seed under rain-fed conditions. Iranian Journal of Seed Research. 9, 63-76[In Persian with English summary]. https://doi.org/10.61186/yujs.9.2.63
Giovanni, G., Silvano, P., Giovanni, D., 2004. Grain yield, nitrogen-use efficiency and baking quality old and modern Italian bread-wheat cultivars grown at different nitrogen levels. European Journal of Agronomy. 21, 181-182.  https://doi.org/10.1016/j.eja.2003.08.001
Gulnaz, S., Sajjad, M., Khaliq, I., Khan, A.S. Khan, S.H., 2011. Relationship among coleoptile length, plant height and tillering capacity for developing improved wheat varieties. The International Journal of Agriculture and Biology. 13, 130–133. https://doi.org/10.5555/20113079525
Han, Y., Li, A., Li, F., Zhao, M., Wang, W., 2012. Characterization of a wheat (Triticum aestivum L.) expansin gene, TaEXPB23, involved in the abiotic stress response and phytohormone regulation. Plant Physiology and Biochemistry. 54, 49-58. https://doi.org/10.1016/j.plaphy
Hasegawa, P.M., Bressan, R.A., Zhu, J.K., Bohnert, H.J., 2000. Plant cellular and molecular responses to high salinity. Annual Review of Plant Physiology and Plant Molecular Biology. 51, 463-499. https://doi.org/10.1146/annurev.arplant.51.1.463
Khaeim, H., Kende, Z., Balla, I., Gyuricza, C., Eser, A., Tarnawa, Á., 2022. The effect of temperature and water stresses on seed germination and seedling growth of wheat (Triticum aestivum L.). Sustainability. 14, 3887. https://doi.org/10.3390/su14073887
Khojamli, R., Zaynali Nezhad, K., Nasrollahnejad Ghomi, A., Bagherikia, S., 2022. Evaluation of bread wheat genotypes under drought stress conditions in seedling stage using drought indices. Environmental Stresses in Crop Sciences ,14, 887-899. [[In Persian with English summary]. https://doi.org/10.22077/escs.2020.3202.1820
Lee, M.H., Kim, K.M., W.G., Kang, C.S., Choi, C., 2022. Comparison of gene expression changes in three wheat varieties with different susceptibilities to heat stress Using RNA-Seq Analysis. International Journal of Molecular Sciences. 23(18),10734. https://doi.org/10.3390/ijms231810734
Li, G., Bai, G., Carver, B.F., Elliott, N.C., Bennett, R.S., Wu, Y., 2017. Genome-wide association study reveals genetic architecture of coleoptile length in wheat. Theoretical and Applied Genetics. 130, 391–401. https://doi.org/10.1007/s00122-016-2820-1
Li, Y., Zhang, Y., Cui, J., Wang, X., Li, M., Zhang, L., Kang, J., 2024. Genome-wide identification, phylogenetic and expression analysis of expansin gene family in Medicago sativa L. International Journal of Molecular Sciences. 25, 4700. https://doi.org/10.3390/ijms25094700
Li, A., Yang Han, Y., Wang, X., Hui Chen, Y., Rong Zhao, M., Zhou, S., Wang, W., 2015. Root-specific expression of wheat expansin gene TaEXPB23 enhances root growth and water stress tolerance in tobacco, Environmental and Experimental Botany. 110, 73-84. https://doi.org/10.1016/j.envexpbot.2014.10.002
Mohan, A., Schillinger, W.F, Gill, K.S., 2013. Wheat seedling emergence from deep planting depths and its relationship with coleoptile length. PLoS One. 8(9), p.e73314. https://doi.org/10.1371/journal.pone.0073314
Ozturk, A., Bayram, S., Haliloglu, K., Aydin, M., Çaglar, O., Bulut, S., 2014. Characterization for drought resistance at early stages of wheat genotypes based on survival, coleoptile length, and seedling vigor. Turkish Journal of Agriculture and Forestry. 38, 824 -837. https://doi.org/10.3906/tar-1402-57
Pfaffl, M.W., 2001. A new mathematical model for relative quantification in real-time RT-PCR. Nucleic Acids Research. 29, e45. https://doi.org/10.1093/nar/29.9.e45
Qi, S., Liu, S., Wen, Y., 2025. Analysis of Expansin genes in Cucurbitaceae and identification of candidate genes for stress resistance. Scientific Reports. 15, 36163. https://doi.org/10.1038/s41598-025-18901-2
Rebetzke, G.R., Appels, R., Morrison, A.D., Richards, R.A., McDonald, G., Ellis, M. H., Spielmeyer, W., Bonnet, G., 2001. Quantitative trait loci on chromosome 4B for coleoptiles length and early vigor in wheat. Crop and Pasture Science. 52, 1221-1234. https://doi.org/10.1071/AR01042
Reymond, P., Weber, H., Damond, M., Farmer., E.E., 2000. Differential gene expression in response to mechanical wounding and insect feeding in Arabidopsis. Plant Cell. 12, 707-720. https://doi.org/10.1105/tpc.12.5.707
Reynolds, M.P., Rebetzke, G., Pellegrineschi, A., Trethowan, R., 2006. Drought adaptation in wheat. In: Ribaut, J.M. (ed.), Drought Adaptation in Cereals. New York, NY, USA: Food Products Press. pp. 401–446.
Saleem, M., 2003. Response of durum and bread wheat genotypes to drought stress: Biomass and yield components. Asian Journal of Plant Sciences. 2, 290-293. https://doi.org/10.3923/ajps.2003.290.293
Sanjari, P.A., Yazdansepas, A., 2008. Mobilization of dry matter and its relation with drought stress in wheat genotypes. Journal of Agricultural Science and Technology. 11, 121-129.
Singh, K., Shukla, S., Kadam, S., Kumar Semwal, V., Kumar Singh, N., Khanna- Chopra, R., 2014. Genomic regions and underlying candidate genes associated with coleoptile length under deep sowing conditions in a wheat RIL population. Plant Biochemistry and Biotechnology. 24, 324–330. https://doi.org/10.1007/s13562-014-0277-3
Wei, N., Zhang, S., Liu, Y., Wang, J., Wu, B., Zhao, J., Qiao, L., Zheng, X., Wang, J., Zheng, J., 2022. Genome-wide association study of coleoptile length with Shanxi wheat. Frontiers in Plant Science. 13, 1016551. https://doi.org/10.3389/fpls.2022.1016551
Whan, B.R., 1995. The emergence of semidwarf and standard wheats, and its association with coleoptile length. Australian Journal of Experimental Agriculture. 16, 411-416. https://doi.org/10.1071/EA9760411
Wu, Y., Sharp, R.E., Durachko, D.M., Cosgrove, D.J., 1996. Growth maintenance of the maize primary root at low water potentials involves increases in cell wall extension properties, expansin activity, and wall susceptibility to expansins. Plant Physiology. 111, 765-772. https://doi.org/10.1104/pp.111.3.765
Xing, S.C., Li, F., Guo, Q.F., Liu, D.R., Zhao, X.X., Wang, W., 2009. The involvement of an expansin geneTaEXPB23 from wheat in regulating plant cell growth. Biologia Plantarum. 53, 429- 434. 10.1007/s10535-009-0082-3
Yagmur, M.A., Kaydan, D., 2009. The effects of different sowing depth on grain yield and some grain yield components in wheat (Triticum aestivum L.) cultivars under dryland conditions. African Journal of Biotechnology. 8, 196-201.  https://doi.org/10.4314/ajb.v8i2.59766
Zhao, W., Liu, L., Shen, Q., Yang, J., Han, X., Tian, F., Wu, J., 2020 Effects of water stress on photosynthesis, yield, and water use efficiency in winter wheat. Water. 12, 2127. https://doi.org/10.3390/w12082127
Environmental Stresses in Crop Sciences

Articles in Press, Accepted Manuscript
Available Online from 07 July 2026

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  • Receive Date: 02 February 2025
  • Revise Date: 07 January 2026
  • Accept Date: 31 January 2026

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