The genus Solanum comprises three food crops (potato, tomato, and eggplant), which are consumed on daily basis worldwide and also producers of notorious anti-nutritional steroidal glycoalkaloids (SGAs). Hydroxylated SGAs (i.e. leptinines) serve as precursors for leptines that act as defenses against Colorado Potato Beetle (Leptinotarsa decemlineata Say), an important pest of potato worldwide. However, SGA hydroxylating enzymes remain unknown. Here, we discover that 2-OXOGLUTARATE-DEPENDENT-DIOXYGENASE (2-ODD) enzymes catalyze SGA-hydroxylation across various Solanum species. In contrast to cultivated potato, Solanum chacoense, a widespread wild potato species, has evolved a 2-ODD enzyme leading to the formation of leptinines. Furthermore, we find a related 2-ODD in tomato that catalyzes the hydroxylation of the bitter α-tomatine to hydroxytomatine, the first committed step in the chemical shift towards downstream ripening-associated non-bitter SGAs (e.g. esculeoside A). This 2-ODD enzyme prevents bitterness in ripe tomato fruit consumed today which otherwise would remain unpleasant in taste and more toxic.

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The genomic DNA profiles of 48 chickpea cultivars released in nine countries and of historical significance to the chickpea breeding programs at ICRISAT and in Ethiopia were evaluated using 48 simple sequence repeat (SSR) markers. Across the cultivars, a total of 504 alleles representing the 48 SSR loci were detected with frequencies ranging from three to 22 (mean 10.5) alleles per locus. The polymorphism information content (PIC) for the SSR markers varied from 0.37 to 0.91 (mean 0.77). A subset of only three highly informative SSR markers (TA176, TA2, TA180) enabled complete discrimination among all 48 chickpea cultivars tested. Hierarchical neighbour-joining UPGMA cluster analysis based on simple matching dissimilarity matrix resolved the 48 cultivars into two major clusters representing desi and kabuli types. These cluster groupings of the cultivars were consistent with the pedigree information available for the cultivars as to the phenotypic classes of chickpea types. Analysis of the temporal patterns of the SSR diversity by classifying 48 chickpea cultivars into four periods of release revealed increasing tendencies in the overall genetic diversity from 0.42 for the earliest varieties developed in the 1970s to 0.62 for those released in the 1980s, and reached a maximum and equivalent level of 0.72 for the varieties developed in the 1990s and 2000s. Overall, the study ascertained that SSRs provide powerful marker tools in revealing genetic diversity and relationships in chickpeas, thereby proving useful for selection of parents in breeding programs and also for DNA fingerprint identification of cultivars.

The differential transport characteristics of NAA and 2,4-D in cestrum cut flowers were reflected in differential activation of the Ce-IAA genes identified in the floret AZ. Therefore, Aux/IAA genes can be used as molecular markers to measure auxin activity, which reflects free auxin level in the AZ. Two of the identified genes, Ce-IAA1 and Ce-IAA5, may also have a regulatory role in abscission.

Article Information The experiment was conducted at Melkassa Agricultural Research Center, Ethiopia with the objective to evaluate the effects of different concentrations and combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and gibberellic acid (GA3) spray on vegetative and reproductive growth components of tomato. The experiment consists of two tomato varieties, one processing (Roma VF) and one fresh market (Fetan), three levels of 2,4-D (0, 5 and 10 ppm) and four levels of GA3 (0, 10, 15 and 20 ppm) arranged in 2x3x4 factorial combinations, in Randomized Completed Block design with three replications. Data were collected on qualitative parameters (vegetative, reproductive growth and external fruit color) through visual observation, and quantitative parameters (seed number per fruit, seed weight per fruit, fruit shape index and average fruit weight). Qualitative data were analyzed using analysis of variance (ANOVA) by SAS (2002) software and mean separation was carried out by DMRT at 5% probability level. The result indicated that tomato plant treated with 2,4-D intended to have increased stem thickness, decreased leaf size induced epinastic and flower bud abscission in both cultivars while GA3 treatment has no retarded growth and flower bud abscission. Application of 2,4-D has responsible in the development of seedless parthenocarpic fruit with increased size but with unfilled cavities especially at higher concentration. On the other hand, GA3 at lower concentration results in normal fruit and seed development but as its concentration increases it results in the development of more proportion of smaller fruits per plant and formation of blotchy ripening on the fruit. Combined application of the two PGRs at lowers concentrations seems to result in the intermediate effects of both PGRs in single application. In general, concentration of the PGRs used and genetic background of the variety determine the response of tomato growth, fruit setting, seed formation and final marketable fruit size.