This study aimed to develop the cacao (Theobroma cacao L.) in vitro regeneration system through somatic embryogenesis on kinetin supplemented DKW medium and somaclonal variation assessment using SSR markers. Callus were initiated from basal petal and staminoid explants cultured on callus induction (CI) medium contained DKW basalt salts and kinetin:2,4-D ratios of 1:15.5, 1:7.8 or 1:3.9 and then transferred onto secondary callus growth (SCG) medium contained WPM basalt salts and kinetin:2,4-D ratios of 1:7.8 or 1:3.9. The calli were then subsequently transferred onto embryo development medium contained DKW basal salts with or without the addition of amino acids, adenine or activated charcoal for the formation of somatic embryos. Nine cacao genotypes were tested for their ability to develop somatic embryos. Results of this study indicated DKW medium supplemented with Kinetin in combination with 2,4-D effectively induced cacao somatic embryogenesis. The highest somatic embryos formation was abtained from kinetin:2,4-D ratio of 1:3.9 and 1:7.8 in CI and SCG medium respectively. Cacao genotype responses were highly explant type dependent. The developed method resulted in a high percentage of somatic embryo formation (5.6-66.7%), germination (50%) and plantlet conversion (65%) and a medium percentage of somaclonal variations based on SSRs marker analysis.

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Sudarsono S., Elina J., Giyanto, Sukma D. (2018): Pathogen causing Phalaenopsis soft rot disease -16S rDNA and virulence characterisation. Plant Protect. Sci., 54: 1-8.The pathogen causing Phalaenopsis soft rot disease and developed detached leaf inoculation methods were identified. Based on its 16S rDNA sequences, the pathogen causing soft rot disease in Phalaenopsis was Erwinia chrysanthemi/ dickeya chrysanthemi. Both virulent and avirulent strains were revealed. The detached leaf inoculation assay for E. chrysanthemi/d. chrysanthemi resistance evaluation included wounding and inoculating the detached leaf with 10 8 CFU/ml of bacteria. Soft rot disease symptoms in the inoculated detached leaf were measurable at 20 h after inoculation. The detached leaf assay was applicable for evaluating Phalaenopsis germplasm and progeny resistance in Phalaenopsis breeding programs.

Phalaenopsis amabilis, commonly known in Indonesia as 'Anggrek Bulan' is one of the Orchidaceae species typically having large (7-12 cm), pure white flowers with yellow coloration and some red stripes on its labellum (Handoyo, 2010). Based on their perianth morphology, there are six types of Phal. amabilis, such as Taiwan, Sumatera, Irian Jaya, Java, Borneo, and Grandiflora types. The Phal. amabilis from Sumatera has smaller perianth than those from Java and Borneo while Phal. grandiflora from Borneo is characterized as having the largest flower and more than 5 cm petals (Ikedo, n.d.). As in many orchid species, illegal harvest, forest destruction, and climatic changes may contribute to the decline of their natural populations (Crain & Tremblay, 2014; Crain & Tremblay, 2017; Fay, 2018). Therefore, it is necessary to develop concerted efforts for ex situ conservation of endangered orchid species before it becomes extinct. The development of ex-situ conservation requires the use of tissue culture as the alternative technology for clonal propagation (Merritt, Hay, Swarts, Sommerville, & Dixon, 2014). Various tissues and organs have been used as explants to initiate propagation of Phalaenopsis, such as leaf (Balilashaki, Naderi, Kalantari,

Drought is a major constrain in crop production that reduce growth and cause yield loss of up to 70%. Transcription factor plays a major role in cellular regulation and physical changes of plants as a response to stress. A number of transcription factors, such as CBF/DREB, NAC, zinc finger protein are regulators during stress. The Oryza sativa NAC6 (OsNAC6) gene is one of the transcription factor in rice that can regulate gene expression during stress conditions. Thus, pCambia 1305 harboring OsNAC6 chimaeric gene with CaMV 35S promoter was introduced into rice zygotic embryo using Agrobacterium tumefaciens mediated transformation to regenerate transgenic rice overexpressing the transgene. As many as 39 putative transgenic lines in which 21 lines possitively harbored hpt gene have been regenerated. The positive identification of hpt in the regenerated transgenic rice indirectly indicated integration of the targeted OsNAC6 since both transgenes were part of the same T-DNA. Further analysis indicated the presence of 1-3 copies of transgene integration in the genome. The expression of OsNAC6 transgene in the transgenic rice line#C.73, C.83 and C.91 were higher than wild type non-transgenic one. Further analysis indicated those three transgenic lines carrying OsNAC6 transgene exhibited higher tolerance against drought and salinity stresses. Moreover, three known stress-associated regulatory genes (AP2, Zincfinger protein and MYB) were up-regulated in those three transgenic lines. These findings demonstrated that OsNAC6 might be a candidate of stress-responsive NAC regulatory gene that can be used to develop either drought or salt tolerant tolerant transgenic plants.