Xiao Min Bie

Background: Tiller number is a factor determining panicle number and grain yield in wheat (Triticum aestivum). Auxin plays an important role in the regulation of branch production. PIN-FORMED 1 (PIN1), an auxin efflux carrier, plays a role in the regulation of tiller number in rice (Oryza sativa); however, little is known on the roles of PIN1 in wheat. Results: Nine homologs of TaPIN1 genes were identified in wheat, of which TaPIN1-6 genes showed higher expression in the stem apex and young leaf in wheat, and the TaPIN1-6a protein was localized in the plasma membrane. The down-expression of TaPIN1s increased the tiller number in TaPIN1-RNA interference (TaPIN1-RNAi) transgenic wheat plants, indicating that auxin might mediate the axillary bud production. By contrast, the spikelet number, grain number per panicle, and the 1000-grain weight were decreased in the TaPIN1-RNAi transgenic wheat plants compared with those in the wild type. In summary, a reduction of TaPIN1s expression increased the tiller number and grain yield per plant of wheat. Conclusions: Phylogenetic analysis and protein structure of nine TaPIN1 proteins were analyzed, and subcellular localization of TaPIN1-6a was located in the plasma membrane. Knock-down expression of TaPIN1 genes increased the tiller number of transgenic wheat lines. Our study suggests that TaPIN1s is required for the regulation of grain yield in wheat.

Background: Tiller number is a factor determining panicle number and grain yield in wheat (Triticum aestivum L.). Auxin plays an important role in the regulation of branch production. PIN-FORMED 1 (PIN1), an auxin efflux carrier, plays a role in the regulation of tiller number in rice (Oryza sativa); however, little is known on the roles of PIN1 in wheat. Results: Nine homologs of TaPIN1 genes were identified in wheat, of which TaPIN1-6 genes showed higher expression in the stem apex and young leaf in wheat, and the TaPIN1-6a protein was localized in the plasma membrane. The down-expression of TaPIN1s increased the tiller number in TaPIN1-RNA interference (TaPIN1-RNAi) transgenic wheat plants, indicating that auxin might mediate the axillary bud production. By contrast, the spikelet number, grain number per panicle, and the 1000-grain weight were decreased in the TaPIN1-RNAi transgenic wheat plants compared with those in the wild type. Conclusions: Phylogenetic analysis and expression patterns of nine TaPIN1 genes, and their protein structures and subcellular localization of TaPIN1-6a protein were analyzed. Down-regulated expression of TaPIN1 genes increased the tiller numbers of transgenic wheat lines. Our study suggests that TaPIN1s is required for the regulation of grain yield in wheat.

Histone acetylation modification plays a vital role in plant cell division and differentiation. However, the function on wheat mature embryo culture has not been reported. Here, we used the mature embryo of wheat genotypes including CB037, Fielder, and Chinese Spring (CS) as materials to analyze the effects of different concentrations of trichostatin A (TSA) and sodium butyrate (SB) on plant regeneration efficiency. The results showed that, compared with the control group, the induction rates of embryogenic callus and green shoot were significantly increased with the addition of 0.5 µM TSA, while they were reduced under treatment of 2.5 µM TSA on wheat mature embryo. With the respective addition of 200 µM and 1000 µM SB, regeneration frequency of three genotypes was enhanced, especially in Fielder, which reached significant difference compared with the control group. Unfortunately, 0.5 µM TSA and 200 µM SB combination had no apparent effect on wheat regeneration frequency. The results indicated that TSA and SB increase plant regeneration in common wheat. In addition, TSA had a common effect and SB had different effect among genotypes on wheat regeneration frequency. The mechanism of action needs further investigation.