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Presenter

Liuling Yan, Oklahoma State University, USA

Outline

The spike architecture is one of the most important agronomic traits that influence grain yield in wheat (Triticum aestivum). In our recent study, we initially cloned a dominant allele TaCol-B5 on chromosome arm 7BL that increases the number of spikelets per spike in common wheat. The gene was named TaCol-B5 to be more consistent with its orthologue (CONSTANS-like 5) in other plant species.
After cloned, TaCol-B5 showed association with increases in the length of the spike, the number of grains per spike, and the number of spikes per plant. When constitutively overexpressed, TaCol-B5 was found to enhance field-based grain yield by 11.9%. The natural variation between the two alleles relied on a single-nucleotide polymorphism that resulted in a critical amino acid substitution, so that TaCol-B5 protein but not Tacol-B5 protein was phosphorylated by the serine/threonine protein kinase TaK4. The edited Tacol-B5 gene, through CRISPR/Cas9 gene editing technology, altered heading date and plant height.
Another critical finding in this study is that the TaCol-B5 allele for higher grain yield was cloned from CItr17600, which is an accession from CIMMYT, but this allele was found in ancestral emmer wheat but only 2% of an international modern wheat variety panel (more than 1,600 accessions).
The story on TaCol-B5 is not over yet but just a starting point in a roadmap for molecular improvement of grain yield. We will discuss about perspectives of TaCol-B5 in establishing ideal plant and spike architectures to increase grain yield in wheat.

Reference

• Zhang X, Jia H, Li T, Wu J, Nagarajan R, Lei L, Powers C, Kan CC, Hua W, Liu Z, Chen C, Carver BF, Yan L. (2022) TaCol-B5 modifies spike architecture and enhances grain yield in wheat. Science. 376:180-183. https://www.science.org/doi/10.1126/science.abm0717

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