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Paecilomyces javanicus is an entomopathogenic fungus of coleopteran and lepidopteran insects. Here we report on cloning, characterization, and expression patterns of a chitinase from P. javanicus. A strong chitinase activity was detected in P. javanicus cultures added to chitin. The full-length cDNA, designated PjChi-1, was cloned from mycelia by using both degenerate primer/reverse transcription polymerase chain reaction (RT-PCR) amplification and 5'-/3'-RACE extension. The 1.18-kb cDNA gene contains a 1035-bp open reading frame and encodes a 345-amino acid polypeptide with a deduced molecular mass of 37 kDa. A conserved motif for chitinase activity -F82DGIDIDWE90- was present in deduced amino acid sequence. Both RT-PCR and Northern analysis revealed that the expression of the PjChi gene was constitutive at low level, but enhanced to high level when chitin was the substrate. Fungal inhibitory assay showed that PjChi-1 inhibited the growth of phytopathogenic fungi such as Sclerotium rolfsii, Colletotrichum gloeosporioides, Aspergillus nidulans, and Rhizoctonia solani.

The hypocotyl and internodal segments from in vitro grown seedlings of Feronia limonia (L.) Swingle (wood apple) were cultivated on Murashige and Skoog's (1962, MS) medium supplemented with N 6 -benzyladenine (BA) or adenine (ADE) or kinetin (KN) at 0.5 to 5 µM. The optimum response was recorded on the medium containing 2 µM BA. An average of 12 and 8 shoots were developed from hypocotyl and internodal explants, respectively, after eight weeks of culture. The shoots were excised, and the residual explants were transferred to fresh medium where again they developed shoots. Up to three such passages resulted in the production of shoots from repeatedly subcultured explants and an average of 24 -36 shoots per explant was obtained. The in vitro developed shoots produced roots when transferred to half strength MS medium supplemented with 1 µM 1-naphthaleneacetic acid (NAA). The developed plantlets were successfully transferred to mixture of soil, sand and coco-peat (1:1:1) and hardened in controlled environment. Hardened plants were transplanted to soil in greenhouse.

Salt tolerance status at early seedling stage in 30 rice varieties including two tolerant (Pokkali and CSR-36) and two susceptible (IR-29 and IR-64) checks was assessed under different levels of salinity (0, 4, 8 and 16 dS m-1) created by salt mixture of NaCl, CaCl 2 , Na 2 SO 4 in 7:2:1 ratio. Overall salinity tolerance indices clearly reflected that 17 varieties including the two tolerant checks were highly tolerant, seven varieties exhibited moderately tolerant, whereas six varieties including the two susceptible checks had highly susceptible response to salt stress. Molecular profiling of 13 tolerant and 5 susceptible rice varieties by using 24 SSR markers revealed 8.5 alleles per primer with altogether 114 shared and 91 unique allelic variants. Considering the allele number, polymorphism information content and polymorphism percent, SSR primers RM 302, RM 8094, RM 10665, RM 10694, RM 10748 and RM 10825 appeared to be highly polymorphic and comparatively more informative. Hierarchical classification and spatial distribution patterns based on amplification profiles dependent similarity indices unambiguously discriminated these 18 varieties in accordance with their salt tolerance response. Sequential exclusion of primers in further analysis led to validation of RM 140, RM 1287, RM 3412, RM 10745, RM 10764 and RM 10772 for their efficiency to distinguish salt tolerant varieties from susceptible ones. A specific combination of either four (RM 1287, RM 3412, RM 10764 and RM 10772) or even two markers (RM 1287 and RM 3412) also seemed to be equally effective in discrimination of entries according to their salt stress responsiveness. Principal coordinate analysis completely corroborated hierarchical classification of the varieties. Salt tolerance donors identified and SSR primers validated in the present study may be further utilized in the development of salt stress tolerant varieties of rice.

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