Article by Watchara Phetluan watchara.phe@ku.th

  “Rice” is one of the crops of great importance to the economy and food security, especially in Thailand, where rice is the staple food. But today rice cultivation faces drought, causing a shortage of water for farming.

Several studies have shown that reducing the number of stomata in plants can help improve water use efficiency (WUE), so plants use less water for growing without affecting their food production (photosynthesis), and tolerate water shortage for longer.

However, most stomatal research is based on Arabidopsis thaliana a model plant, so knowledge about stomata in rice (Oryza sativa) is still needed.

This study investigated the link between stomatal density and genetics in Thai rice varieties, with the aim of finding genes linked to or controlling stomatal density.

The study used Genome-wide association studies (GWAS), analyzing stomatal density data together with SNP markers obtained from whole genome sequences of 235 Thai rice varieties. The research team found 5 SNP markers linked to stomatal density, located on chromosomes 2, 3, 9 and 12. However, the result was only a broad region of DNA and could not yet pinpoint the target gene.

The research team therefore continued the study to find the target gene, and in the end discovered a gene significantly linked to stomatal density, namely the gene LOC_Os02g43170 (B-BOX zinc finger family protein) which had never before been reported to be related to stomatal traits.

The team then confirmed that this gene is related to stomatal traits by gene knock out, making the target gene non-functional. The result was a significant decrease in stomatal density compared with normal rice, which indicated that LOC_Os02g43170 is linked to stomatal number or stomatal density.

This study will lead to developing and breeding rice that can withstand climate variability, or “climate change”, which we are facing today.

Reference

Candidate genes affecting stomatal density in rice (Oryza sativa L.) identified by genome‐wide association

Watchara Phetluan a b, Samart Wanchana c, Wanchana Aesomnuk c, Julian Adams d, Mutiara K. Pitaloka e, Vinitchan Ruanjaichon c, Apichart Vanavichit e f, Theerayut Toojinda c, Julie E. Gray d, Siwaret Arikit e f

DOI: 10.1016/j.plantsci.2023.111624