Three Novel er1 Alleles and Their Functional Markers for Breeding Resistance to Powdery Mildew (Erysiphe pisi) in Pea.

Powdery mildew caused by Erysiphe pisi DC is a global notorious disease on peas. Deploying resistance pea cultivars is the most efficient and environmentally friendly method for disease control. This study focuses on revealing the resistance genes in three pea germplasms and developing their functional markers for resistance breeding. The identification of resistance genes involved genetic mapping and the sequencing of the pea mildew resistance locus O homolog PsMLO1 gene. To confirm the heredity of three resistant germplasms, they were crossed with susceptible cultivars to generate F1, F2, and F2:3 populations. The F1 generation exhibited susceptibility to E. pisi, whereas the segregation patterns in subsequent generations adhered to the 3:1 (susceptible: resistant) and 1:2:1 (susceptible homozygotes: heterozygotes: resistant homozygotes) ratios, indicating that powdery mildew resistance was governed by a single recessive gene in each germplasm. Analysis of er1-linked markers and genetic mapping suggested that the resistance genes could be er1 alleles in these germplasms. The multiple clone sequencing results of the three homologous PsMLO1 genes showed they were novel er1 alleles, named er1-15, er1-16, and er1-17. The er1-15 and er1-16 were caused by 1-bp deletion at position 335 (A) and 429 (T) in exon 3, respectively, whereas er1-17 was caused by a 1-bp insertion at position 248 in exon 3, causing a frame-shift mutation and premature termination of PsMLO1 protein translation. Their respective functional markers, kompetitive allele-specific PCR (KASP)-er1-15, KASP-er1-16, and KASP-er1-17, were successfully developed and validated in respective mapping populations and pea germplasms. These results provide valuable tools for pea breeding resistance to E. pisi.

An Emerging Disease of Chickpea, Basal Stem Rot Caused by Diaporthe aspalathi in China.

Chickpea (Cicer arietinum L.) is an important legume crop worldwide. An emerging disease, basal stem rot with obvious wilt symptoms, was observed in the upper part of chickpea plants during the disease survey in Qiubei County of Yunnan Province. Three fungal isolates (ZD36-1, ZD36-2, and ZD36-3) were obtained from the diseased tissue of chickpea plants collected from the field. Those isolates were morphologically found to be similar to Diaporthe aspalathi. Molecular sequence analyses of multiple gene regions (ITS, tef1, tub2, cal, and his3) indicated that the three isolates showed a high identity with D. aspalathi. Pathogenicity and host range tests of the isolates were performed on the original host chickpea and eight other legume crops. The isolates were strongly pathogenic to chickpea and appeared highly pathogenic to soybean, cowpea, and mung bean; moderated or mild pathogenic to adzuki bean and common bean; however, the isolates did not cause symptoms on grass pea (Lathyrus sativus). Diaporthe aspalathi was previously reported as a main pathogen causing the southern stem canker in soybean. To our knowledge, this is the first report of D. aspalathi inducing basal stem rot on chickpea worldwide.

The Establishment of Evaluation Models for the Cooking Suitability of Different Pork Muscles.

Pork is the main meat consumed by Chinese people. In this study, the sensory quality of four muscles (loin, shoulder, belly, and ham) under three cooking methods (boiling, scalding, and roasting) was examined, and the edible quality and nutritional quality of fresh meat were determined at the same time. Principal component analysis, cluster analysis, correlation analysis, and analysis of the coefficient of variation were used to determine key quality indicators, from which comprehensive quality evaluation equations were established. The results showed that, when meat was boiled, the comprehensive quality evaluation model was Y=0.1537X1+0.1805X2+0.2145X3+0.2233X4+0.2281X5 (X1~X5 are a*, fat, odor, tenderness, and flavor, respectively) and the most suitable muscle was belly; when meat slices were scalded in a hot pot, the comprehensive quality evaluation model was Y=0.1541X1+0.1787X2+0.2160X3+0.2174X4+0.2337X5 (X1~X5 are a*, fat, odor, tenderness, and flavor, respectively) and the most suitable muscle was belly; when meat was roasted, the comprehensive quality evaluation model was Y=0.1539X1+0.1557X2+0.1572X3+0.1677X4+0.1808X5+0.1845X6 (X1~X6 are flavor, marbling, elasticity, cooked flesh color, tenderness, and flesh color, respectively), and the most suitable muscles were belly and shoulder.

Characterization and identification of pork flavor compounds and their precursors in Chinese indigenous pig breeds by volatile profiling and multivariate analysis.

Chinese indigenous pigs are favored for their rich flavor, which is generated through complex reactions involving lipid-oxidation-related flavor precursors. In this research, we characterized the aroma compounds and fatty acids of representative Chinese pig breeds by gas chromatography-olfactometry-mass spectrometry (GC-O-MS) and GC-ion mobility spectrometry (GC-IMS) with multivariate analysis. A total of 79 volatile compounds were identified, among which 15 compounds were selected as odorants in pork. According to multivariate statistical analysis, some odorants, including hexanal, 1-octen-3-ol, 2,3-octanedione, (E, E)-2,4-decadienal and dodecanal could be discriminative compounds explaining breed-originated differences in flavor profiles. As confirmed by partial least squares regression (PLS-R), some fatty acids, including C18:1n9c, C22:6n3 and C18:3n3, were major precursors for the formation of rich flavor in indigenous pig breeds. These results revealed that fatty acids and volatile compounds were breed-dependent, and the differences in flavor were related to the variance in the fatty acid content.

The Effects of Different Natural Plant Extracts on the Formation of Polycyclic Aromatic Hydrocarbons (PAHs) in Roast Duck.

Polycyclic aromatic hydrocarbons (PAHs) with high carcinogenicity and mutagenicity may be generated in roast duck during high-temperature roasting. Natural extracts with antioxidant effects may inhibit the formation of PAHs. The objective of this study was to compare the effects of green tea extract (GTE); extract of bamboo leaves (EBL); grape seed extract (GSE) and rosemary extract (RE) on PAHs in roast duck to obtain the optimum extract and present a guidance for reducing PAHs in roast duck. The total phenol content and antioxidant capacity of the four extracts were measured, and the PAH changes in the roast duck caused by the four extracts were detected. The total phenol content of GTE was the highest, 277 mg gallic acid equivalent (GAE)/g, while RE was the lowest at 85 mg GAE/g. The antioxidant capacity of RE was 1.9 mmol Trolox/g, which was significantly lower than that of the other three. The four extracts inhibited PAHs formation in roast duck to varying degrees: When the concentration was 25 g/kg, the best inhibitory effects on Benzo [a] pyrene (BaP) and PAH4 (BaP, BaA, BbF and CHR) were obtained from GTE, with inhibition rates of 75.8% and 79.7%, respectively, while the weakest inhibition rates, 32.7% and 43.6%, respectively, were from RE.

Screening out important substances for distinguishing Chinese indigenous pork and hybrid pork and identifying different pork muscles by analyzing the fatty acid and nucleotide contents.

Fatty acids and nucleotides are major contributors of pork flavor, which are key quality traits influencing consumers' preference. In this study, we investigated the contents of nucleotides (inosinic acid, inosine, and hypoxanthine) and 26 fatty acids by high-performance liquid chromatography and gas chromatography in longissimus dorsi and semimembranous muscle of four breeds (Dongbei Min pig, Beijing Black pig, Wuzhishan pig, and DLY pigs). Combining with multivariate statistics, we found significant differences in the nucleotides and fatty acids compositions among the breeds and muscles. Furthermore, the content of total unsaturated fatty acids and DHA were higher in native pigs than crossbred pigs. This study provides a theoretical basis for understanding the composition of flavor precursor substances, as well as for the identification of different muscles.