• Journal of Practical Agriculture & Fisheries Research
• /
• v.12 no.1
• /
• pp.47-52
• /
• 2010

Squash cultivars of Cucurbita moschata have good fresh quality, but their viny growth habit hinders wide cultivation under structure. On the other hand, 'Zucchini' varieties of C. pepo have bush growth habit and better growth ability under the low temperature condition than C. moschata, but have inferior flesh quality. To combine desirable characteristics of the two species, many attempts have been exerted to obtain interspecific hybrids. A shootless phenomenon was found among segregating populations; the cotyledon expanded normally but further shoot growth. The inheritance of the character was investigated in F₂ and BC₁F₂ populations. The segregation ratios indicated that the shoot-lacking characteristics is expressed by double recessive gene pairs.

• Korean Journal of Plant Resources
• /
• v.11
• /
• pp.40-47
• /
• 1998

When the leaves, roots and stem segments of seedling of Polygonatum odoratum were cultured on Murashige and Skoog medium with 2.0mg/l BAP, stem segments were the most efficient explants for adventitious shoot inductino. To observe the efficient combination of growth regulators on the adventitious shoot formation , stem segments were cultured on MS medium with various kinds of cytokinins (BAP, kinetin, zeatin). From this experiment, cytokinin treatement was prerequisite for theadventitious shoot formatino,especially BAP was the most effective. Auxin (NAA or IBA) in combination with cyotokinin highly enhanced the adventitious shoot formation. Twenty five percents of explants produced the adventitious shoots on medium with 2.0mg/l BAP solely, while 83% of explants produced the adventitious shoots on medium with 2.0mg/l BAP and 0.1mg/l IBA. Root formationform adventitious shoot was promoted after transfer to 1/2 MS medium supplemented with 0.1mg/l IBA and 0.5mg/l zeatin, thereafter the plantlets with shoots and roots were cultured on 1/2MS medium lacking growth regulators. When the stem segments were cultured to MS medium with 1.0mg/l 2,4 NAA and IBA , yellow and nodulous cali were formed from the stem segments which were developed into adventitious roots. These roots were actively grew after transferred to MS liquid medium lacking growth regulators.

• Plant Biotechnology Reports
• /
• v.4 no.1
• /
• pp.53-59
• /
• 2010

A specific deleted version of ARABIDOPSIS RESPONSE REGULATOR1 (ARR1) lacking the signal receiver domain (1.152 amino acids)-coding sequence, referred to as $ARR1{\Delta}DDK$, was amplified using Arabidopsis thaliana cDNA prepared from adult leaves and transferred into the genome of Nicotiana tabacum cv. Samsun under the transcriptional control of a ${\beta}$-estradiol-inducible expression system. The ectopic expression of $ARR1{\Delta}DDK$ affected the morphology of transgenic seedlings and their segments in vitro. In the presence of an inducer, ${\beta}$-estradiol, ectopic expression of $ARR1{\Delta}DDK$ induced only the formation of soft, pseudo-bulbous tissue in the root tip region of intact seedlings, which appeared similar to callus generated on a hypocotyl segment in the presence of 2,4-D and 6-benzyladenine (BA), both at $1\;{\mu}M$. Those callus tissues on the root tip region could not generate shoots unless $1\;{\mu}M$ BA was supplied. In segment culture, ectopic expression of $ARR1{\Delta}DDK$ induced calluslike tissue around the cut-end of cotyledon and hypocotyl segments with occasional shoot formation, suggesting that the expression of $ARR1{\Delta}DDK$ could substitute for the effects of cytokinin on these segments. Additionally, treatment with only ${\beta}$-estradiol induced NtWUS, a WUS ortholog in tobacco, which was detected during the process of callus tissue formation in the root tip region and also in cotyledon or hypocotyl segments. These findings suggest that the NtWUS might be associated in the transdifferentiation process caused by the functional regulation of $ARR1{\Delta}DDK$ in transgenic tobacco seedlings.

• Molecules and Cells
• /
• v.25 no.1
• /
• pp.30-42
• /
• 2008

The disease-specific (dsp) region and the hypersensitive response and pathogenicity (hrp) genes, including the hrpW, $hrpN_{Ep}$, and hrpC operons have previously been sequenced in Erwinia pyrifoliae WT3 [Shrestha et al. (2005a)]. In this study, the remaining hrp genes, including the hrpC, hrpA, hrpS, hrpXY, hrpL and hrpJ operons, were determined. The hrp genes cluster (ca. 38 kb) was comprised of eight transcriptional units and contained nine hrc (hrp conserved) genes. The genetic organization of the hrp/hrc genes and their orientation for the transcriptions were also similar to and collinear with those of E. amylovora, showing ${\geq}80%$ homologies. However, ORFU1 and ORFU2 of unknown functions, present between the hrpA and hrpS operons of E. amylovora, were absent in E. pyrifoliae. To determine the HR active domains, several proteins were prepared from truncated fragments of the N-terminal and the C-terminal regions of $HrpN_{Ep}$ protein of E. pyrifoliae. The proteins prepared from the N-terminal region elicited HR, but not from those of the C-terminal region indicating that HR active domains are located in only N-terminal region of the $HrpN_{Ep}$ protein. Two synthetic oligopeptides produced HR on tobacco confirming presence of two HR active domains in the $HrpN_{Ep}$. The HR positive N-terminal fragment ($HN{\Delta}C187$) was further narrowed down by deleting C-terminal amino acids and internal amino acids to investigate whether amino acid insertion region have role in faster and stronger HR activity in $HrpN_{Ep}$ than $HrpN_{Ea}$. The $HrpN_{Ep}$ mutant proteins $HN{\Delta}C187$ (D1AIR), $HN{\Delta}C187$ (D2AIR) and $HN{\Delta}C187$ (DM41) retained similar HR activation to that of wild-type $HrpN_{Ep}$. However, the $HrpN_{Ep}$ mutant protein $HN{\Delta}C187$ (D3AIR) lacking third amino acid insertion region (102 to 113 aa) reduced HR when compared to that of wild-type $HrpN_{Ep}$. Reduction in HR elicitation could not be observed when single amino acids at different positions were substituted at third amino acids insertion region. But, substitution of amino acids at L103R, L106K and L110R showed reduction in HR activity on tobacco suggesting their importance in activation of HR faster in the $HrpN_{Ep}$ although it requires further detailed analysis.

• Journal of Plant Biotechnology
• /
• v.37 no.3
• /
• pp.337-342
• /
• 2010

To establish the optimum conditions of in vitro plant regeneration, the leaf, rhizome, and root explants of Belamcanda chinensis were cultured on the MS medium supplemented with different concentration of 2,4-D and BA. The callus induction was more effective in the root explants than the leaf and rhizome explants, and was the best on MS medium containing 3.0 mg/L 2,4-D or 1.0 mg/L 2,4-D and 3.0 mg/L BA. The highest numbers of shoots were regenerated when callus were cultured on MS medium containing 3.0 mg/L 2,4-D for 4 weeks. However, the multiple shoots were induced on MS medium supplemented with the combination of 2,4-D and BA. The normal root formation from shoot was effective on the MS medium lacking any plant growth regulators. For acclimatization, the regenerated plantlets were cultured on MS medium without sucrose and plant growth regulators for 2 weeks, and then transferred to the pot.

• Journal of Ginseng Research
• /
• v.23 no.3 s.55
• /
• pp.130-134
• /
• 1999

Somatic embryos were induced directly from cotyledon explants of Korean ginseng (Panax ginseng C.A. Meyer) on Murashige and Skoog (MS) medium with 2,4-D, BAP, kinetin or lacking growth regulators. When somatic embryos formed on all media grew to cotyledonary stage, the further development of embryos was ceased and remained in white color. By gibberellic acid (over 1.0 mg/1 $GA_3$) treatment, all the somatic embryos turned rapidly to green and germinated within 3 weeks. Chilling treatment also induced the germination of somatic embryos. The effective temperature regime was $-2^{\circ}C$ for over 8 weeks but more higher temperature than $0^{\circ}C$ did not effective for germination of somatic embryos. Ultrastructural observation revealed that the cotyledon cells of somatic embryos without chilling or $GA_3$ treatment contained numerous lipid reserves, dense cytoplasm, proplastids and non-activated mitochondria with poorly differentiated internal structure, but the cotyledon cells of germinating somatic embryos after chilling or $GA_3$ treatment highly vacuolated and contained well-developed chloroplasts and active state of mitochondria enclosing numerous cristae. The above results indicate that in vitro developed somatic embryos of Panax ginseng may be dormant after mature similar to zygotic embryos.