Petunia Floral Defensins with Unique Prodomains as Novel Candidates for Development of Fusarium Wilt Resistance in Transgenic Banana Plants

Antimicrobial peptides are a potent group of defense active molecules that have been utilized in developing resistance against a multitude of plant pathogens. Floral defensins constitute a group of cysteine-rich peptides showing potent growth inhibition of pathogenic filamentous fungi especially Fusarium oxysporum in vitro. Full length genes coding for two Petunia floral defensins, PhDef1 and PhDef2 having unique C- terminal 31 and 27 amino acid long predicted prodomains, were overexpressed in transgenic banana plants using embryogenic cells as explants for Agrobacterium–mediated genetic transformation. High level constitutive expression of these defensins in elite banana cv. Rasthali led to significant resistance against infection of Fusarium oxysporum f. sp. cubense as shown by in vitro and ex vivo bioassay studies. Transgenic banana lines expressing either of the two defensins were clearly less chlorotic and had significantly less infestation and discoloration in the vital corm region of the plant as compared to untransformed controls. Transgenic banana plants expressing high level of full-length PhDef1 and PhDef2 were phenotypically normal and no stunting was observed. In conclusion, our results suggest that high-level constitutive expression of floral defensins having distinctive prodomains is an efficient strategy for development of fungal resistance in economically important fruit crops like banana

Intraspecific hybridization in “Egusi” melon, Colocynthis citrullus L.

Intraspecific hybridization in Melon, Colocynthis citrullus L. was carried out in the botanical garden of university of Calabar using three varieties namely “sewere” (S) “barablackedge” (BB) and “barawhite edge” (BW). They were crossed in all possible combinations including their reciprocals. Average percentage fruit set of 18.1 was recorded. Colour of young fruits and colour of mature fruits were each found to be controlled by a single gene pair (monogenic inheritance). Chi-square analysis of the data on inheritance showed a good fit between observed and expected ratios in all the populations. Analysis of variance for some growth characters studied showed that most of the hybrids obtained did not differ significantly from their parents (P >0.05) in leaf length, number of leaves per branch, stem width, vine length at maturity and height at branching. However, hybrid BW X BB was found to have produced significantly (

Inheritance of stripe pattern on fruits and seed colour in \"Egusi\" melon, Colocynthis Citrusllus L.

No abstractKeywords: inheritance patterns; fruit stripes; seed colour; Colocynthis citrullusGlobal Journal of Agricultural Sciences Vol. 4(1) 2005: 29-3