Development of high amylose wheat through TILLING.

Area of Science:

• Plant genetics and breeding
• Nutritional science
• Food science

Background:

• Wheat is a global food staple, with ongoing research focused on enhancing its genetic diversity for improved crop traits.
• Modifying wheat starch composition, particularly increasing amylose levels, is a key target for improving human health benefits.
• Higher amylose content in starch correlates with increased resistant starch, which offers health advantages in managing obesity and diabetes.

Purpose of the Study:

• To utilize TILLING (Targeting Induced Local Lesions in Genomes) for identifying novel genetic variations in wheat.
• To develop new wheat varieties with enhanced starch characteristics, specifically high amylose content.
• To create healthier wheat varieties without employing transgenic methods.

Main Methods:

• Employed TILLING to screen for mutations in starch branching enzyme IIa (SBEIIa) genes across wheat genomes (A, B, and D).
• Combined identified SBEIIa mutations through breeding in durum and bread wheat.
• Analyzed high amylose wheat lines for resistant starch levels, SBEIIa RNA expression, starch granule morphology, and protein profiles.

Main Results:

• Identified single nucleotide polymorphisms (SNPs) in SBEIIa genes using TILLING in both durum and bread wheat.
• Developed high amylose wheat varieties (47-55% amylose) with elevated resistant starch compared to wild-type.
• Observed reduced SBEIIa RNA expression, altered starch granule morphology, and modified starch granule protein profiles in high amylose lines.

Conclusions:

• Successfully applied TILLING to introduce desirable traits into complex-genome crops like wheat without genetic modification.
• Developed novel durum and bread wheat lines with significantly increased amylose and resistant starch content through combined SBEIIa mutations.