Understanding the regulation of cereal grain filling: The way forward

Abstract

During grain filling, starch and other nutrients accumulate in the endosperm; this directly determines grain yield and grain quality in crops such as rice (Oryza sativa), maize (Zea mays), and wheat (Triticum aestivum). Grain filling is a complex trait affected by both intrinsic and environmental factors, making it difficult to explore the underlying genetics, molecular regulation, and the application of these genes for breeding. With the development of powerful genetic and molecular techniques, much has been learned about the genes and molecular networks related to grain filling over the past decades. In this review, we highlight the key factors affecting grain filling, including both biological and abiotic factors. We then summarize the key genes controlling grain filling and their roles in this event, including regulators of sugar translocation and starch biosynthesis, phytohormone‐related regulators, and other factors. Finally, we discuss how the current knowledge of valuable grain filling genes could be integrated with strategies for breeding cereal varieties with improved grain yield and quality.

GWAS and transcriptomic analysis identify OsRING315 as a new candidate gene controlling amylose content and gel consistency in rice

“…There were 22 annotated genes within the qAC9-2 and qGC9-2 region (Table S3) based on release 7 of the MSU Rice Genome Annotation Project (Kawahara et al 2013). Since the grain lling stage is the key period for grain quality, and the differentially expressed genes during this stage may result in variant quality (Yang et al 2022;Ma et al 2023). To further localize the candidate genes, the spikes (15-day after owering) of 10 accessions with lower GC (Chr09: 14724296, C allele) and 10 accessions with higher GC (Chr09: 14724296, T allele) were sampled for RNA sequencing, respectively.…”

Spatiotemporal dynamics of the foxtail millet transcriptome during grain filling

“…Among them, grain filling is a key period directly affecting the yield and quality of cereal crops (Saini & Westgate, 1999; Zhou et al, 2013). Starch accumulates continuously in the grain during the grain filling (endosperm development), leading to a rapid increase in grain weight (Ma et al, 2023). The regulation of grain filling is very complex.…”

“…Assimilates produced in the source (leaf) are transferred to the sink (kernel) by the flow (stem) during grain filling (Ma et al, 2023; Schnyder, 1993). It has long been known that upper leaves in cereal crops, especially flag leaves, are important for grain filling.…”

Characterisation of starch properties and physical characteristics in buckwheat (Fagopyrum esculentum Moench.) mutant lacking accumulation of ‘granule‐bound starch synthase a’

“…Low‐amylose starch has been reported in rice and wheat (Christa & Soral‐Śmietana, 2008; Denyer et al, 2001; Deschamps et al, 2008). Amylose concentration is a complex trait in rice (Ikeno, 1914) and is controlled by several factors such as the Waxy ( Wx ) gene (Ma et al, 2023; Sano, 1984). Wx encodes granule‐bound starch synthase I (GBSSI), an enzyme involved in amylose synthesis.…”