Increasing yield of durum wheat (Triticum durum spp.) through overexpression of TON1B
Author(s)
Date Issued
2024
Type
conferenceObject
Abstract
Durum wheat (T. turgidum ssp. durum) stands as a crucial staple in the Mediterranean basin, providing the semolina base for several mediterranean diet foods.
Despite a commendable increase in wheat production over recent decades, it is evident that its current yield is not poised to meet the escalating demands of the growing global population. Wheat yield, a complex polygenic trait influenced by environmental factors, has and has been the subject of intensive research. Notable genes like GW2, TON2, SnKR1, GBS, TPS7, TPP3 and TPP7 have been identified in association with grain shape and size, which in turn can affect the yield of different cereal species.
This study investigates the role of the Tonneau1 (Ton1) gene, focusing on its isoform Ton1b in durum wheat. Ton1, a key player in the TTP (TON1-TRM-PP2A) protein complex, is known for its involvement in preprophase band formation and cell division control in plants1, influencing organs size.
A pCreloxpGEMTeasy-Ton1b2 construct was prepared and used for embryo transformation. The Ton1b coding sequence was placed under the control of an endosperm-specific promoter and terminator, both isolated from the gene encoding the high molecular weight glutenin subunit Dx53.
The obtained intragenic lines showed a significant increase of 100-kernel weight and grain length without negative effects on seeds number. This intriguing outcome challenges the conventional trade-off among key yield-related traits4. These lines also showcased a strategic energy reallocation consisting in a reduction of spike length and spikelet number. Noteworthy, despite shorter spikes, the fertility of all flowers was maintained, optimizing resource allocation for maximum yield.
The biochemical assay to determine the total starch content among intragenic lines and null segregant lines has revealed an increase in all intragenic lines, indicating that the overexpression of Ton1b is directly related to a higher starch content.
This study explores the molecular mechanisms behind the Ton1b-mediated enhancement of durum wheat yield. Using real-time PCR analysis, we evaluated the expression levels of TON1b and a panel of associated genes (CEN1, GW2, TPP3, TPP7, TON2, TPS7, GBS, SnkR1) in intragenic lines compared to null segregants. The intragenic lines showed overexpression of TON1b, leading to the downregulation of CEN1 and upregulation of TON2. The expression trends of other genes varied among the lines, with the IP1 line showing the most promising results according to real-time PCR data.
In conclusion, this study underscores the potential of TON1b in enhancing durum wheat yield, presenting a promising avenue for addressing global food security concerns.