ABSTRACT
In order to understand the difference of quality for Chinese and CIMMYT wheat varieties (lines), we selected 153 wheat germplasm from both China and CIMMYT to explore the contribution relationship of different allelic variation combinations to wheat quality through genotyping and phenotyping, including grain hardness, polyphenol oxidase (PPO) activity, lipoxygenase (LOX) activity, yellow pigment (YP) content and protein content. In terms of flour milling quality, Chinese wheat varieties were mainly carrying Pina-D1a/Pinb-D1b, accounting for 32.0% of the total tested varieties, while the CIMMYT wheat lines were mainly carrying Pina-D1b/Pinb-D1a with 45.8% of the total collection. The distribution frequencies of subunit 1/2* and 5 + 10 were 47.0% and 42.5%, respectively, in CIMMYT varieties, however they were only 31.4% and 13.7% respectively of the Chinese wheat tested varieties. In addition, the proportion of phytoene synthase (PSY) allele, PPO allele and LOX active allele were roughly the same between Chinese and CIMMYT varieties. Based on the present study, we found that Pina gene had a greater impact on grain hardness value than Pinb gene; The influence of PPO-A1 gene on polyphenol oxidase activity was more significant than PPO-D1 gene. The high protein content of varieties mostly containing hardness genes and 1/2*/5 + 10 subunit combinations. Based on the present study, we found that the quality gene distribution of Chinese and CIMMYT varieties was quite different, for instance, the high-quality HMW-GS subunits of Chinese varieties were lower than CIMMYT lines. It will be much useful for Chinese wheat breeders to develop good quality wheat variety by crossing with 3 good strong gluten CIMMYT wheat lines by molecular marker-assisted selection.
ABSTRACT
In order to understand the genetic basis of starch pasting viscosity characteristics of Chinese spring wheat, we assessed the genetic variation of RVA parameters determined by the Rapid Visco Analyser in a panel of 192 Chinese spring wheat accessions grown in Er'shi, Shihezi and Zhaosu during 2012 and 2013 cropping seasons. A genome-wide association study with 47,362 single nucleotide polymorphism (SNP) markers was conducted to detect marker-trait associations using mixed linear model. Phenotypic variations of RVA parameters ranged from 1.6 to 30.7% and broad-sense heritabilities ranged from 0.62 to 0.91. Forty-one SNP markers at 25 loci were significantly associated with seven RVA traits in at least two environments; among these, 20 SNPs were located in coding sequences (CDS) of 18 annotation genes, which can lead to discovering novel genes underpinning starch gelatinization in spring wheat. Haplotype analysis revealed one block for breakdown (BD) on chromosome 3B and two blocks for pasting temperature (T) on chromosome 7B. Cultivars with superior haplotypes at these loci showed better starch pasting viscosity than the average of all cultivars surveyed. The identified loci and associated markers provide valuable sources for future functional characterization and genetic improvement of starch quality in wheat.
ABSTRACT
OBJECTIVES: Obtain endophyte strains with effective resveratrol production from superior grapevine variety Cabernet Sauvignon in Xinjiang and determine related taxonomic position of the strain. RESULTS: Seventy-three strains of endophytes, including 23 strains of bacteria, 14 ones of actinomycetes, 24 fungus and 12 yeasts, were isolated, respectively. The distribution law of endophytes was spring (30.14 %) = summer (30.14 %) < autumn (39.73 %) in different seasons, while the fruit (12.33 %) < leaf (20.55 %) < stem (32.88 %) < root (34.25 %) in different tissues and organs. From the 36 strains of endophytic fungi isolated, seven strains producing polyphenols were screened by ferric chloride-potassium ferricyanide color reaction. C2J6, stable genetic properties producing highly 1.48 mg L(-1) of resveratrol, was identified as Aspergillus niger by 26S rDNA-ITS sequence analysis after thin-layer chromatography sieve analysis, ultra violet wavelength scanning and high performance liquid chromatography, respectively. CONCLUSIONS: There were the certain number and kinds of endophytes in the various tissues of Cabernet Sauvignon, which, to a certain extent, reflected the biological diversity of plant endophytes. The fact that the fungus C2J6 producing resveratrol in grape was acquired attested the special ability of the endophytes to produce the same or similar bioactive substances as the host plants.
