Flowering gene expression in Indonesian long harvest black rice (Oryza sativa L. ‘Cempo Ireng’)

Abstract

Many studies have reported the great potency of black rice as functional food for human diet. Cempo Ireng is one of Indonesian black rice cultivars with the highest content of anthocyanin. However, it also suffers from long harvest period. This experiment aims at investigating the behavior of the flowering genes in order to gain basic information to develop this cultivar. We sampled the leaves' blades of Black Rice 'Cempo Ireng' at 48, 55, 68, 81, and 90 DAP then performed RNA isolation and cDNA synthesis, amplification of targeted flowering genes, and a semi-quantitative analysis to see the expression of flowering genes. Our results showed that the flowering genes Hd3a and RFT1 were redundantly up-regulated to induce flowering in black rice Cempo Ireng under a neutral day condition in a tropical region. We also noted that the patterns of FT-like genes and flowering regulatory genes including FT-L5, OsCOL4 were expressed together with two major flowering genes. FT-like genes were temporally co-expressed with two flowering genes Hd3a and RFT1, whereas the Hd1 had a unique expression pattern. Meanwhile, OsCOL4 as the flowering repressor was only detected in the early stage when the flowering gene Hd3a began to express. The results suggest that black rice Cempo Ireng has similar and conserved flowering pathway under a neutral day condition as indicated in the common rice flowering models.

Potential of Pigmented Rice Variety Cempo Ireng in Rice Breeding Program for Improving Food Sustainability

“…These fl owering genes were investigated by isolated the RNA of the leaves at 48, 55, 68, 81, and 90 days after planted and cDNA synthesis for each sample. The fl owering pathway of Cempo Ireng conserved the common rice fl owering models [19,33].…”

“…Understanding the fl owering pathway of Cempo Ireng is one of the eff ort to shorten the fl owering period in order to increase the yield. Preliminary results identifi ed the fl owering genes Hd3a and RFT1 in Cempo Ireng under neutral day conditions [10,19,20].…”