scholarly journals Characterization of Fusarium Spp. Inciting Vascular Wilt of Tomato and Its Management by a Chaetomium-Based Biocontrol Consortium

2021 ◽  
Vol 12 ◽  
Author(s):  
Govindan Pothiraj ◽  
Zakir Hussain ◽  
Awani Kumar Singh ◽  
Amolkumar U. Solanke ◽  
Rashmi Aggarwal ◽  
...  

Though the vascular wilt of tomato caused by the species of Fusarium is globally reported to be a complex disease in certain countries, for example, India, our studies indicated that the disease is caused by either Fusarium oxysporum f. spp. lycopersici (Fol) or Fusarium solani (FS) with the Fol being widely prevalent. In assessing the genetic diversity of 14 Fol strains representing the four Indian states by the unweighted pair group method with arithmetic averaging using Inter Simple Sequence Repeat (ISSR) amplicons, the strains distinguished themselves into two major clusters showing no correlation with their geographic origin. In pot experiments under polyhouse conditions, the seed dressing and soil application of a talc-based formulation of a biocontrol treatment, TEPF-Sungal-1 (Pseudomonas putida) + S17TH (Trichoderma harzianum) + CG-A (Chaetomium globosum), which inhibited Fol, was equally effective like the cell suspensions and was even better than the fungicidal mixture (copper oxychloride-0.25% + carbendazim-0.1%) in promoting the crop growth (52.3%) and reducing vascular wilt incidence (75%) over the control treatment, despite the challenge of inoculation with a highly pathogenic TOFU-IHBT strain. This was associated with significant expressions of the defense genes, indicating the induction of host resistance by a biocontrol consortium. In field experiments on two locations, the bioconsortium was highly effective in recording maximum mean fruit yields (54.5 and 60%) and a minimum mean vascular wilt incidence (37.5%) in comparison to the untreated control. Thus, Chaetomium-based bioconsortium demonstrated consistency in its performance across the two experiments in 2 years under the two field conditions.

2011 ◽  
Vol 9 (2) ◽  
pp. 210-213 ◽  
Author(s):  
Luís Rocha ◽  
Sandra Martins ◽  
Valdemar Carnide ◽  
Fernando Braga ◽  
Carlos Carvalho

Woad (Isatis tinctoria L.) was introduced in Europe in ancient times to produce indigo, a natural blue pigment used mainly for dyestuff. This species was cultivated in Portugal until the beginning of the 20th century, especially in the inner North and South. A set of nine inter-simple sequence repeat (ISSR) markers generated 177 reproducible fragments, of which 171 were polymorphic. The mean number of fragments/accession was 111, ranging between 100 (Portugal-Coimbra) and 124 (Poland). The total polymorphism observed was 0.3272, the average polymorphism was 0.1784 and the gene differentiation between accessions was 0.4546. Polymorphism ranged between 53.8% (Austria) and 73.1% (Belgium). The genetic relationship among woad accessions was obtained with unweighted pair group method with arithmetic mean dendrogram based on a molecular marker, clearly clustering the woad accessions according to their geographic origin. The genetic diversity observed in this collection shows that there is a considerable potential for its improvement and that ISSR could be used to evaluate intra- and inter-accession similarities in I. tinctoria species.


2021 ◽  
Vol 9 ◽  
Author(s):  
Jyoti Mathur ◽  
P. B. Khare ◽  
Apurva Panwar ◽  
S. A. Ranade

Pteris vittata L. is very common and a widely distributed species belongs to the family Pteridaceae. Various cytotypes from diploid to octaploid is available in this fern species. The present work has been carried out for genetic diversity in this fern both within and between the cytotypes. The molecular analysis at inter- as well as intra-species has been carried out with 57 accessions of P. vittata as well as of other species of Pteris with Microsorium punctatum considered as an out group taxon. For the present study 48 P. vittata (36 tetraploid and 12 pentaploid) and five of other species (four P. cretica, one P. pellucida, one P. tremula, one P. quadriaurita, and two P. ensiformis) accessions were used. The UPGMA (unweighted pair group method with arithmetic mean) dendrograms were generated for each method separately, as well as for all methods cumulatively, after a 1000 replicate bootstrap analysis. In order to determine the utility of each of the method, a comparative statistical assessment was done and marker index (MI), expected average heterozygosity, fraction of polymorphic loci and effective multiplex ratio (EMR) were calculated in case of each of the methods used in the present study. At the level of individual methods highest MI was obtained for directed amplification of minisatellites DNA (DAMD) method. Our findings of the present study concluded that out of the three methods Random Amplified Polymorphic DNA (RAPD), Inter-Simple Sequence Repeat (ISSR), and Directed Amplification of Minisatellite DNA (DAMD), DAMD was the best in term of polymorphism and heterozygosity as scores exhibited highest MI. The different accessions of P. vittata collected from different phytogeographical regions falls into six groups. Out of six clusters, one cluster is of pentaploid cytotype, four clusters are of tetraploid cytotype and one for outgroup taxon (M. punctatum). The result thus showed that within tetraploid, heterozygosity with variable genomic structure exists.


Plant Disease ◽  
2021 ◽  
Author(s):  
Marwa Laribi ◽  
Alireza Akhavan ◽  
Sarrah M'Barek ◽  
Amor Yahyaoui ◽  
Stephen Ernest Strelkov ◽  
...  

Pyrenophora tritici-repentis (Ptr) causes tan spot, an important foliar disease of wheat. A collection of Ptr isolates from Tunisia, located in one of the main secondary centers of diversification of durum wheat, was tested for phenotypic race classification based on virulence on a host differential set, and for the presence of the necrotrophic effector (NE) genes ToxA, ToxB , and toxb by PCR analysis. While races 2, 4, 5, 6, 7, and 8 were identified according to their virulence phenotypes, PCR testing indicated the presence of ‘atypical’ isolates that induced necrosis on the wheat differential ‘Glenlea’, but lacked the expected ToxA gene, suggesting the involvement of other NEs in the Ptr/wheat interaction. Genetic diversity and the Ptr population structure were explored further by examining 59 Tunisian isolates and 35 isolates from Algeria, Azerbaijan, Canada, Iran, and Syria using 24 simple sequence repeat markers. Average genetic diversity, overall gene flow and percentage polymorphic loci were estimated as 0.58, 2.09 and 87%, respectively. Analysis of molecular variance showed that 81% of the genetic variance occurred within populations and 19% between populations. Cluster analysis by the unweighted pair group method indicated that ToxB- isolates grouped together and were distantly related to ToxB+ isolates. Based on Nei’s analysis, the global collection clustered into two distinct groups according to their region of origin. The results suggest that both geographic origin and the host-specificity imposed by different NEs can lead to differentiation among Ptr populations.


2008 ◽  
Vol 88 (2) ◽  
pp. 313-322 ◽  
Author(s):  
S. C. Debnath ◽  
S. Khanizadeh ◽  
A. R. Jamieson ◽  
C. Kempler

The goal of this study was to determine the level of genetic diversity and relatedness among 16 strawberry (Fragaria H ananassa Duch.) cultivars and 11 breeding lines developed in Canada, using Inter Simple Sequence Repeat (ISSR) markers. Seventeen primers generated 225 polymorphic ISSR-PCR bands. Cluster analysis by the unweighted pair-group method with arithmetic averages (UPGMA) revealed a substantial degree of genetic similarity among the genotypes ranging from 63 to 77% that were in agreement with the principal coordinate (PCO) analysis. Geographical distribution for the place of breeding program explained only 1.4% of total variation as revealed by analysis of molecular variance (AMOVA). The ISSR markers detected a sufficient degree of polymorphism to differentiate among strawberry genotypes, making this technology valuable for cultivar identification and for the more efficient choice of parents in current strawberry breeding programs. Key words: Fragaria × ananassa, DNA fingerprinting, multivariate analysis, breeding, genetic similarity


2014 ◽  
Vol 13 (3) ◽  
pp. 238-246 ◽  
Author(s):  
Eliana Monteverde ◽  
Guillermo A. Galván ◽  
Pablo Speranza

In Uruguay, onion (Allium cepa L.) germplasm is mainly derived from the genetic material introduced by several waves of European immigrants and subsequently multiplied by household farmers, resulting in a wealth of locally adapted populations. This study examined the genetic diversity in a collection of 27 local onion populations and two cultivars derived from them. A total of 843 onion plants were fingerprinted, and 83 inter-simple sequence repeat polymorphic bands were generated. Analysis of molecular variance showed high diversity within the populations (66% of the total variation). Some short-day populations from different geographical origins were grouped together by the unweighted pair-group method using arithmetic averages, principal coordinate analysis and cluster analysis, while the more extensively sampled long- and intermediate-day populations showed a widespread distribution, with no significant subgrouping among them. This weakly structured gene pool is probably the consequence of seed and bulb exchange between farmers and natural inter-pollination. Nevertheless, a Bayesian analysis allowed the distinction of four genetic backgrounds of alleles in the whole collection, and populations were predominately assigned to each genetic background. In addition, mitochondrial variants determining normal (N) pollen fertility or the sterile S or T types were analysed for the same set of plants using specific primers. Most accessions showed a proportion of male-sterile individuals. Cytoplasm type T was the most represented (26 out of 29 accessions), and cytoplasm type S was found in a low proportion of individuals in seven populations. Uruguayan onion germplasm maintains a low degree of genetic differentiation despite the small cultivated area and intense seed exchange, probably due in part to different market purposes based on the growing cycle.


Genome ◽  
2002 ◽  
Vol 45 (6) ◽  
pp. 1175-1180 ◽  
Author(s):  
F J Massawe ◽  
M Dickinson ◽  
J A Roberts ◽  
S N Azam-Ali

Bambara groundnut (Vigna subterranea (L.) Verdc), an African indigenous legume, is popular in most parts of Africa. The present study was undertaken to establish genetic relationships among 16 cultivated bambara groundnut landraces using fluorescence-based amplified fragment length polymorphism (AFLP) markers. Seven selective primer combinations generated 504 amplification products, ranging from 50 to 400 bp. Several landrace-specific products were identified that could be effectively used to produce landrace-specific markers for identification purposes. On average, each primer combination generated 72 amplified products that were detectable by an ABI Prism 310 DNA sequencer. The polymorphisms obtained ranged from 68.0 to 98.0%, with an average of 84.0%. The primer pairs M-ACA + P-GCC and M-ACA + P-GGA produced more polymorphic fragments than any other primer pairs and were better at differentiating landraces. The dendrogram generated by the UPGMA (unweighted pair-group method with arithmetic averaging) grouped 16 landraces into 3 clusters, mainly according to their place of collection or geographic origin. DipC1995 and Malawi5 were the most genetically related landraces. AFLP analysis provided sufficient polymorphism to determine the amount of genetic diversity and to establish genetic relationships in bambara groundnut landraces. The results will help in the formulation of marker-assisted breeding in bambara groundnut.Key words: under-utilized, African legume, molecular markers.


2007 ◽  
Vol 132 (3) ◽  
pp. 357-367 ◽  
Author(s):  
P. Escribano ◽  
M.A. Viruel ◽  
J.I. Hormaza

Cherimoya (Annona cherimola Mill.) is an underused fruit crop with a clear niche for expansion in subtropical climates. In this study, 16 simple sequence repeat (SSR) loci were used to find molecular polymorphisms among 279 cherimoya accessions from a worldwide ex situ field germplasm collection. A total of 79 amplification fragments were amplified with 16 pairs of SSR primers, with an average of 4.9 bands/SSR. Mean expected and observed heterozygosities averaged 0.53 and 0.44, respectively. The total value for the probability of identity was 4.34 × 10−8. The SSRs studied resulted in 267 different fingerprinting profiles, of which 258 were unique genotypes; the rest were putative cases of synonymies or mislabeling errors. Unweighted pair group method with arithmetic averages (UPGMA) cluster analysis indicated the relationships among the analyzed accessions, showing some specific groups related to their geographical origins. Analysis of molecular variance (AMOVA) was performed to examine the distribution of genetic variation of the 148 accessions collected from putative cherimoya origin areas in Ecuador and Peru, showing that the major variations occurred within valleys in each country. The results confirmed the usefulness of microsatellites for identification of genetic diversity and geographic origin of cherimoya and are discussed in terms of their implications for ex situ conservation of cherimoya genetic resources.


2006 ◽  
Vol 86 (1) ◽  
pp. 251-257 ◽  
Author(s):  
Zhao Weiguo ◽  
Zhou Zhihua ◽  
Miao Xuexia ◽  
Wang Sibao ◽  
Zhang Lin ◽  
...  

The genetic diversity of 27 mulberry (Morus spp.) genotypes mainly from China was investigated using inter-simple sequence repeat (ISSR) markers to assist in addressing breeding objectives and conserving existing genetic resources. Of the 22 primers screened, 15 produced highly reproducible ISSR bands. Using these 15 primers, 138 discernible DNA fragments were generated with 126 (91.3%) being polymorphic, indicating considerable genetic variation among the mulberry genotypes studied. Genetic similarity ranged from 0.6014 between Yu 2 and Yu 711 to 0.9493 between Cuizhisang and Dejiang 10. The phenetic dendrogram based on ISSR data generated by the unweighed pair group method with arithmetical averages (UPGMA) method grouped the 27 accessions into two major clusters: cluster I, cultivated mulberry species (M. multicaulis Perr., M. alba Linn., M. atropurpurea oxb., M. bombycis Kiodz., M. australis Poir., M. rotundiloba Kiodz., M. alba var. pendula Dipp., M. alba var. macrophylla Loud., and M. alba var. venose Delile.); and cluster II, wild mulberry species (M. cathayana Hemsl., M. laevigata Wall., M. wittiorum Hand-Mazz., M. nigra Linn., and M. mongolica Schneid.). Our molecular analyses agree with the existing morphological classification of Morus and clarify the genetic relationships among mulberry species. Key words: Morus L., genetic diversity, inter-simple sequence repeat, relatedness


2011 ◽  
Vol 101 (4) ◽  
pp. 416-424 ◽  
Author(s):  
C. F. Munhoz ◽  
B. Weiss ◽  
L. R. Hanai ◽  
M. I. Zucchi ◽  
M. H. P. Fungaro ◽  
...  

Xanthomonas axonopodis pv. passiflorae causes bacterial spot in passion fruit. It attacks the purple and yellow passion fruit as well as the sweet passion fruit. The diversity of 87 isolates of pv. passiflorae collected from across 22 fruit orchards in Brazil was evaluated using molecular profiles and statistical procedures, including an unweighted pair-group method with arithmetical averages-based dendrogram, analysis of molecular variance (AMOVA), and an assigning test that provides information on genetic structure at the population level. Isolates from another eight pathovars were included in the molecular analyses and all were shown to have a distinct repetitive sequence-based polymerase chain reaction profile. Amplified fragment length polymorphism technique revealed considerable diversity among isolates of pv. passiflorae, and AMOVA showed that most of the variance (49.4%) was due to differences between localities. Cluster analysis revealed that most genotypic clusters were homogeneous and that variance was associated primarily with geographic origin. The disease adversely affects fruit production and may kill infected plants. A method for rapid diagnosis of the pathogen, even before the disease symptoms become evident, has value for producers. Here, a set of primers (Xapas) was designed by exploiting a single-nucleotide polymorphism between the sequences of the intergenic 16S-23S rRNA spacer region of the pathovars. Xapas was shown to effectively detect all pv. passiflorae isolates and is recommended for disease diagnosis in passion fruit orchards.


2015 ◽  
Vol 14 (1) ◽  
pp. 77-80 ◽  
Author(s):  
Pratima Sinha ◽  
Md Aminul Islam ◽  
Madan Singh Negi ◽  
Shashi Bhushan Tripathi

We report on identification of core collection from 192 accessions collected from 12 Indian states and five other countries based on 109 polymorphic amplified fragment length polymorphism (AFLP) markers. Pairwise Jaccard's similarity coefficient for accessions varied from 0.25 to 1 with a maximum genetic distance of 0.75 obtained between accessions Jc428 (from Mexico) and J204 (from Madurai, Tamil Nadu). Both UPGMA (Unweighted Pair Group Method of Arithmetic Averages) clustering and principal coordinate analyses showed similar grouping of accessions in three major clusters in which Mexican accessions clustered separately from Indian, Chinese and African accessions. Results obtained from analysis of molecular variance indicated that 59% of the genetic variation was distributed among the populations, while 41% of variation was within the populations. A total of 16 (8.3% of the entire collection) core accessions were identified, which contained the entire allelic diversity of 192 accessions with respect to the sampled AFLP loci. The core accessions would be highly useful for future genetic improvement of Jatropha. To the best of our knowledge, this is the first report on identification of core accessions in Jatropha.


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