The responsive characteristics of phytochrome genes to photoperiod, abiotic stresses and identification of their key natural variation sites in foxtail millet (Setaria italica L.) / 生物工程学报

The responsive patterns of phytochrome gene family members to photoperiod and abiotic stresses were comparatively analyzed and the favorable natural variation sites of these genes were identified. This would help understand the mechanism of phytochrome gene family in photoperiod-regulated growth and development and abiotic stress response. In addition, it may facilitate the molecular marker assisted selection of key traits in foxtail millet. In this study, we used RT-PCR to clone three phytochrome genes SiPHYA, SiPHYB and SiPHYC from ultra-late maturity millet landrace variety 'Maosu'. After primary bioinformatics analysis, we studied the photoperiod control mode and the characteristics of these genes in responding to five abiotic stresses including polyethylene glycol (PEG)-simulated drought, natural drought, abscisic acid (ABA), high temperature and NaCl by fluorescence quantitative PCR. Finally, we detected the mutation sites of the three genes among 160 foxtail millet materials and performed haplotype analysis to determine the genes' functional effect. We found that the cloned cDNA sequences of gene SiPHYA, SiPHYB and SiPHYC were 3 981, 3 953 and 3 764 bp respectively, which contained complete coding regions. Gene SiPHYB and SiPHYC showed closer evolutionary relationship. Photoperiod regulated all of the three genes, but showed more profound effects on diurnal expression pattern of SiPHYB, SiPHYC than that of SiPHYA. Under short-day, when near heading, the expression levels of SiPHYA and SiPHYB were significantly lower than that under long-day, indicating their roles in suppressing heading of foxtail millet under long-day. SiPHYB and SiPHYC were responsive to PEG-simulated drought, natural drought, ABA and high temperature stresses together. SiPHYA and SiPHYB responded differently to salt stress, whereas SiPHYC did not respond to salt stress. Re-sequencing of 160 foxtail millet materials revealed that SiPHYB was highly conservative. Two missense mutations of SiPHYA, such as single nucleotide polymorphism (SNP) 7 034 522C→T and SNP7 036 657G→C, led to delaying heading and increasing plant height. One missense mutation of SiPHYC, such as SNP5 414 823G→T, led to shortening heading under short-day and delaying heading under long-day, as well as increasing plant height and panicle length regardless of photo-thermal conditions. Photoperiod showed different regulatory effects on SiPHYA, SiPHYB and SiPHYC. SiPHYB and SiPHYC jointly responded to various abiotic stresses except for the salt stress. Compared with the reference genotype, mutation genotypes of SiPHYA and SiPHYC delayed heading and increased plant height and panicle length.

Analysis of genomic DNA methylation level in foxtail millet by Methylation Sensitive Amplified Polymorphism / 生物工程学报

DNA methylation is an important type of epigenetic modification in eukaryotes. In order to research genome-wide methylation levels and patterns in foxtail millet (Setaria italica), the Methylation Sensitive Amplified Polymorphism (MSAP) analysis (employing double digestion with EcoR I and Hpa II/Msp I) was established and applied in two foxtail millet cultivars (Chaogu 58 and Yugu 1). The results showed that 32 pairs of MSAP primers were selected from 100 MSAP primers, and 1 615 and 1 482 clearly distinguishable and reproducible bands were amplified from Chaogu 58 and Yugu 1 respectively, including 3 types of methylation patterns. Cytosine methylation levels of CCGG context in Chaogu 58 and Yugu 1 were characterized as 6.93% and 8.77% respectively. Such different genomic DNA methylation levels between two foxtail millet varieties may provide a preliminary reference for the cultivation of this crop from a novel epigenetic viewpoint.

Efficacy of Millets in the Development of Low Glycemic Index Sweets for Diabetics

Introduction: Three types of burfi (a sweet confection), namely, foxtail millet burfi (FMb), barnyard millet burfi (BMb) and control Bengal gram flour burfi (CBGFb) were developed for the consumption of diabetics. Methods: The flour blends for FMb and BMb contained 43% of foxtail millet and barnyard millet flour, respectively and 57% of bengal gram flour. The CBGFb was prepared by using 100% Bengal gram flour and served as control. The burfis were analysed for sensory quality, acceptability, storage stability, nutritional quality, glycemic index (GI) and glycemic load (GL). Results: All the three burfis were acceptable to diabetic as well as non-diabetic subjects and could be stored easily for 15 days under ambient conditions. The millet burfis possessed fibre and starch contents which contributed to a low GI value of 37.5 for FMb compared to the control. The GL values were 14.7, 17 and 17.9 for FMb, BMb and CBGFb, respectively. Conclusion: The millet, especially foxtail millet which had a low GI value has the potential of being served to diabetics in the form of sweets.

The Effect of Seed-borne Mycoflora from Sorghum and Foxtail Millet Seeds on Germination and Disease Transmission

The seed-borne mycoflora of sorghum and foxtail millet collected from different growing areas in South Korea were isolated and taxonomically identified using dry inspection, standard blotter and the agar plate method. We investigated the in vitro and in vivo germination rates of disinfected and non-disinfected seeds of sorghum and foxtail millet using sterilized and unsterilized soil. The percent recovery of seed-borne mycoflora from the seed components of sorghum and foxtail millet seeds was determined and an infection experiment using the dominant species was evaluated for seedling emergence and mortality. A higher number of seed-borne fungi was observed in sorghum compared to that of foxtail millet. Eighteen fungal genera with 34 fungal species were identified from the seeds of sorghum and 13 genera with 22 species were identified from the seeds of foxtail millet. Five dominant species such as Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme and Phoma sp. were recorded as seed-borne mycoflora in sorghum and 4 dominant species (Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme) were observed in foxtail millet. The in vitro and in vivo germination rates were higher using disinfected seeds and sterilized soil. More seed-borne fungi were recovered from the pericarp compared to the endosperm and seed embryo. The percent recovery of seed-borne fungi ranged from 2.22% to 60.0%, and Alternaria alternata, Curvularia lunata and 4 species of Fusarium were isolated from the endosperm and embryo of sorghum and foxtail millet. Inoculation of the dominant seed-borne fungi showed considerable mortality of seedlings. All the transmitted seed-borne fungi might well be a primary source of infection of sorghum and foxtail millet crops.

Factors Influencing Agrobacterium-mediated Transformation of Foxtail Millet (Setaria italica) / 中国生物化学与分子生物学报

An efficient and repeatable approach in transforming the foxtail millet (Setaria italica ) using Agrobacterium LBA4404 horboring the plasmid pBI121 was established. Factors affecting transformation efficiency were investigated including the genotype, explants, the density of bacteria, the duration for inoculation and co-cultivation, and the concentration of acetosyringone in the medium. The maximum transformation conditions were: the callus induced from inflorescence was used as explant; the duration for inoculation with Agrobacterium at low cell density was 30-40 min; for the co-cultivation , the suitable concentration of acetosyringone in the medium was 0.1 mmol/L, and the duration was 2 days.