Exploit natural variation within the Triticum genus to increase the size of maternal floral organs and wheat grain

Chen, Yi (2023) Exploit natural variation within the Triticum genus to increase the size of maternal floral organs and wheat grain. Doctoral thesis, University of East Anglia.

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Abstract

With the increasing population size and the climate crisis, there is an urgent need to stabilize or even increase yield of wheat which accounts for significant portion of human’s caloric intake. Grain yield is influenced by different yield components such as grain number per spike, grain weight and tillering ability. To improve these traits in wheat, we need a better understanding of the genetic mechanism underlying them. The aim of this thesis is to apply the newly available wheat genomic tools to better understand the genetic basis of yield components traits.

Grain size and weight is an important component of the final grain yield. The wheat subspecie, T. ispahanicum, was first identified due to its elongated glume which was controlled by a single locus, P2. P2 was hypothesized by previous study to be on chromosome 7B but with genetic mapping, I found that P2 is instead on chromosome 6A (Chapter two). With further fine-mapping and gene-editing, I identified the underlying gene of P2 to be SHORT VEGETATIVE PHASE (SVP-A1). SVP-A1 allele from T. ispahanicum carries a 482-bp promoter deletion that removes conserved DNA motifs. With gene-editing, I demonstrated that these motifs play a role in regulating SVP-A1 expression and the promoter deletion is sufficient to increase glume and grain length under glasshouse and field condition (Chapter three).

Spike architecture can impact the final grain yield. To better understand the genetic basis that influence spike architecture, we investigated the genetic basis of four wheat mutants with compact spike morphology (Chapter four). In this study, we performed mRNA-sequencing on compact spike near-isogenic lines (NIL) to identify the candidate genes underlying the compact spike phenotype. We found that the underlying gene for the compact spike mutant MA17648 and ANK-15 to be APETALA2-like (AP2L) transcription factors which have well-characterized effect on spike length in wheat and barley based on previous genetic studies.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Kitty Laine
Date Deposited:	12 Nov 2024 13:05
Last Modified:	12 Nov 2024 13:05
URI:	https://ueaeprints.uea.ac.uk/id/eprint/97644
DOI:

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