Genetic diversity analysis of faba bean (Vicia faba L.) germplasms using sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

To investigate genetic diversity and relationships of 101 faba bean (Vicia faba L.), landraces and varieties from different provinces of China and abroad were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE). A total of 2625 unambiguous and stable bands from 101 germplasms were detected, and 36 different bands were classified according to the electrophoretic mobility patterns of the proteins as determined by the SDS-PAGE analysis, of which 16 were polymorphic. Besides the common bands, the protein bands of 92, 75, 62, 40, 34, 17, and 13 kDa presented the highest frequencies of 92.08, 90.10, 99.01, 95.05, 95.05, 98.02, and 95.05%, respectively. The other 29 polymorphic protein bands showed higher polymorphism with 16.09 polymorphic bands in average. The genetic similarity of the 101 genotypes tested varied from 0.6111 to 0.9722, with an average of 0.7122. Cluster analysis divided the 101 genotypes into six major clusters, which was consistent with the systematic classification of faba bean done in previous studies. The overall results indicated that SDS-PAGE was a useful tool for genetic diversity analysis and laid a solid foundation for future faba bean breeding.

Genetic diversity and relationship of global faba bean (Vicia faba L.) germplasm revealed by ISSR markers.

Genetic diversity and relationships of 802 faba bean (Vicia faba L.) landraces and varieties from different geographical locations of China and abroad were examined using ISSR markers. A total of 212 repeatable amplified bands were generated with 11 ISSR primers, of which 209 were polymorphic. Accessions from North China showed highest genetic diversity, while accessions from central China showed low level of diversity. Chinese spring faba bean germplasm was clearly separated from Chinese winter faba bean, based on principal component analysis and UPGMA clustering analysis. Winter accessions from Zhejiang (East China), Jiangxi (East China), Sichuan (Southwest China) and Guizhou (Southwest China) were quite distinct to that from other provinces in China. Great differentiation between Chinese accessions and those from rest of the world was shown with a UPGMA dendrogram. AMOVA analyses demonstrated large variation and differentiation within and among groups of accessions from China. As a continental geographic group, accessions from Europe were genetically closer to those from North Africa. Based on ISSR data, grouping results of accessions from Asia, Europe and Africa were obviously associated with their geographical origin. The overall results indicated that the genetic relationship of faba bean germplasm was closely associated with their geographical origin and their ecological habit.

Molecular variation among Chinese and global winter faba bean germplasm.

A sample of winter faba bean germplasm from China was compared with germplasm from outside China, using AFLP analyses. Both sets of germplasm were obtained from the National Genebank of China, Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences, Beijing, China. A sample of 39 winter type accessions from outside of China and 204 Chinese landraces and varieties (201 winter types and 3 spring types) were characterized with 10 AFLP primers. These detected 266 polymorphic bands. The Chinese germplasm was clearly separated from the rest of the world in principal component analysis and clustering analysis, with the spring types from China showing the greatest separation. Yunnan germplasm, both landraces and commercial varieties, showed the greatest separation among the germplasm of Chinese winter faba bean provinces. The landraces/varieties from Anhui, Zhejiang, Sichuan, Jianxi, Guizhou and Fujian provinces clustered in a central group.

Nodule infection by bean yellow mosaic virus in Vicia faba and molecular characterization of it.

Root nodules infection of different faba bean (Vicia faba L.) cultivars by bean yellow mosaic virus (BYMV) and the effect of the disease on the specific activity of the nodule are reported. The disease reduced the fresh weights of tops, roots, root nodules and induced premature nodule decay and/or nodule drop. Six local cultivars: Barekat, Iranshahri, Saraziri, Aljazayeri, Shakhbozi and Zohre of faba bean were selected and inoculated with BYMV under greenhouse conditions. ELISA test (DAS-ELISA) with specific BYMV antibody (DSMZ AS0471) demonstrated that nodules from faba bean plants which had been inoculated with BYMV contain the virus too. Susceptibility of different faba bean cultivars was analyzed by ELISA. The relative accumulations of BYMV in the nodules were evaluated by mean ELISA values (OD405) of BYMV. There was significantly difference in cultivars. Cultivars went more susceptible from Barekat to Iranshahri, Saraziri, Aljazayeri, Shakhbozi and Zohre. High susceptibility of Zohre was confirmed in a second experiment including visual evaluation and DAS ELISA. Analysis by IC-RT-PCR revealed the presence of the virus in all nodules and amplified a 970 bp fragment with specific designed primers (Forward primer (5'-CT(AC) CA(AG) ATG GAG AA(CT) CC(CT) GC 3') and Reverse primer (5'-CCA AAG TTC CAA TCA CCA CC 3').

Molecular characterization and detection of Vicia cryptic virus in different Vicia faba cultivars.

After extraction of double-stranded (ds) RNAs from Vicia faba, dsRNA1 and dsRNA2 of Vicia cryptic virus (VCV), a member of the genus Alphacryptovirus (family Partitiviridae), were detected in six out of seven different cultivars by agarose gel electrophoresis. In attempts to sequence the complete VCV genome, the dsRNA1 and dsRNA2 sequences from a total of five different V. faba cultivars were determined. Analysis of these sequences indicated that V. faba cultivars contain almost indistinguishable VCV sequences. The larger dsRNA1 was 2012 bp in length and contained a major open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp). The smaller dsRNA2 was 1779 bp in length and comprised a single ORF on its plus-strand encoding the coat protein (CP). The sequences of the dsRNA1 and dsRNA2 ORFs shared highest amino acid sequence identities (84 and 56%, respectively) with the corresponding gene products of the alphacryptovirus white clover cryptic virus 1 (WCCV-1). The 5'-terminal untranslated regions of dsRNA1 and dsRNA2 of VCV were highly conserved and were strikingly similar to the corresponding regions of WCCV-1. RdRp amino acid sequence alignments revealed conserved motifs, which correlate with the phylogenetic clustering of the family Partitiviridae.

[Responses of different Vicia faba varieties' photosynthetic characteristics to Pb pollution].

In a field experiment of simulated Pb pollution (40 and 250 mg x kg(-1)), this paper investigated the net photosynthetic rate, stomal conductance, transpiration rate, intercellular CO2 concentration, water use efficiency, and chlorophyll content of three Vicia faba varieties K0883, K0502 and K0697. The results showed that under Pb pollution, there was no significant variation in the transpiration rate and stomal conductance of the three varieties, but their chlorophyll content increased in different extents. When the Pb concentration was 250 mg x kg(-1), the net photosynthetic rate and water use efficiency of K0883 were increased by 121.80% and 193.70%, respectively, while its intercellular CO2 concentration was decreased by 42.76%. According to the Perturbation test based on the responses of test photosynthetic characteristics, the Pb-resistance of the three varieties was in the sequence of K0883 > K0697 > K0502. It was concluded that the responses of different photosynthetic indexes and different Vicia faba varieties to small dosage Pb pollution were differed, and the intraspecific difference could only be detected by the integration of all photosynthetic indices.

Natural resistance to Clover yellow vein virus in beans controlled by a single recessive locus.

We characterized the resistance of the common bean cv. Jolanda to Clover yellow vein virus no. 30 (ClYVV). After inoculation, the virus was detected in neither inoculated nor upper leaves, suggesting that the resistance operates at either the viral replication or cell-to-cell movement level. To analyze the mechanism of resistance, we developed a green fluorescent protein (GFP)-tagged ClYVV, and monitored GFP fluorescence at sites of infection on ClYVV-inoculated leaves. No GFP fluorescence was detected in Jolanda, whereas its expression in single cells and spread on inoculated leaves were observed clearly in susceptible cultivars. ClYVV-introduced Jolanda cells were found to be still viable; therefore, it is unlikely that the restriction of multiplication was due to rapid cell death. Genetic analysis indicated that a single recessive locus controlled the resistant phenotype of Jolanda. We designated this locus desc (determinant of susceptibility to ClYVV). Meanwhile, a spontaneous mutant virus that overcomes the resistance (ClYVV-Br) was isolated. Inoculation assays using chimeric viruses suggested that a viral genome-linked protein (VPg) might be the avirulence determinant. The resistance mechanism may be associated with the role of VPg in the viral infection cycle.