• The Plant Pathology Journal
• /
• 제28권4호
• /
• pp.364-372
• /
• 2012

Xanthomonas oryzae pv. oryzae causing bacterial leaf blight disease in rice produces and secretes Hpa1 protein that belongs to harpin protein family. Previously it was reported that Hpa1 induced defense responses when it was produced in tobacco. In this study, we expressed hpa1 gene in rice and Arabidopsis to examine the effects of Hpa1 expression on disease resistance to both fungal and bacterial pathogens. Expression of hpa1 gene in rice enhanced disease resistance to both X. oryzae pv. oryzae and Magnaporthe grisea. Interestingly, individual transgenic rice plants could be divided into four groups, depending on responses to both pathogens. hpa1 expression in Arabidopsis also enhanced disease resistance to both Botrytis cineria and Xanthomonas campestris pv. campestris. To examine genes that are up-regulated in the transgenic rice plants after inoculation with X. oryzae pv. oryzae, known defense-related genes were assessed, and also microarray analysis with the Rice 5 K DNA chip was performed. Interestingly, expression of OsACS1 gene, which was found as the gene that showed the highest induction, was induced earlier and stronger than that in the wild type plant. These results indicate that hpa1 expression in the diverse plant species, including monocot and dicot, can enhance disease resistance to both fungal and bacterial plant pathogens.

• The Plant Pathology Journal
• /
• 제30권2호
• /
• pp.168-177
• /
• 2014

Plant has possessed diverse stress signals from outside and maintained its fitness. Out of such plant responses, it is well known that mitogen-activated protein kinase (MAPK) cascade plays important role in wounding and pathogen attack in most dicot plants. However, little is understood about its role in wounding response for the economically important monocot rice plant. In this study, therefore, the involvement of MAPK was investigated to understand the wounding signaling pathway in rice. The OsMPK1 was rapidly activated by wounding within 10 min, and OsMPK1 was also activated by challenge of rice blast fungus. Further analysis revealed that OsMKK4, the upstream kinase of OsMPK1, phosphorylated OsMPK1 by wounding in vivo. Furthermore, OsMPK1 directly interacted with a rice defense-related transcription factor OsWRKY53. To understand a functional link between MAPK and its target transcription factor, we showed that OsMPK1 activated by the constitutively active mutant $OsMKK4^{DD}$ phosphorylated OsWRKY53 in vitro. Taken together, components involving in the wounding signaling pathway, OsMKK4-OsMPK1-OsWRKY53, can be important players in regulating crosstalk between abiotic stress and biotic stress.

• Plant Biotechnology Reports
• /
• 제3권4호
• /
• pp.325-331
• /
• 2009

To efficiently express a gene of interest in transgenic plants, the choice of promoter is a crucial factor as it directly affects the expression of the transgene that will yield the desired phenotype. The Arabidopsis ${\beta}-carotene$ hydroxylase 1 gene (AtBch1) shows constitutive and ubiquitous expression and was thus selected as one of best candidates for constitutive promoter analysis by both in silico northern blotting and semi-quantitative RT-PCR analysis. To investigate AtBch1 promoter activity, the 1,981-bp 5'-upstream region of this gene was fused with ${\beta}-glucuronidase$ (GUS) and transformed into Arabidopsis. Through the molecular characterization of transgenic leaf tissues, the AtBch1 promoter generated strong activity that drives 1.8- and 2-fold higher GUS expression than the cauliflower mosaic virus 35S (35S) promoter at the transcriptional and translational levels, respectively. Furthermore, the GUS enzyme activity driven by the AtBch1 promoter was 2.8-fold higher than that produced by the 35S promoter. By histochemical GUS staining, the ubiquitous expression of the AtBch1 promoter was observed in all tissues of Arabidopsis. Semi-quantitative RT-PCR analysis with different tissues further showed that this promoter serves as a strong constitutive driver of transgene expression in dicot plants.

• Molecules and Cells
• /
• 제39권3호
• /
• pp.250-257
• /
• 2016

Abiotic stresses such as drought and low temperature critically restrict plant growth, reproduction, and productivity. Higher plants have developed various defense strategies against these unfavorable conditions. CaPUB1 (Capsicum annuum Putative U-box protein 1) is a hot pepper U-box E3 Ub ligase. Transgenic Arabidopsis plants that constitutively expressed CaPUB1 exhibited drought-sensitive phenotypes, suggesting that it functions as a negative regulator of the drought stress response. In this study, CaPUB1 was over-expressed in rice (Oryza sativa L.), and the phenotypic properties of transgenic rice plants were examined in terms of their drought and cold stress tolerance. Ubi:CaPUB1 T3 transgenic rice plants displayed phenotypes hypersensitive to dehydration, suggesting that its role in the negative regulation of drought stress response is conserved in dicot Arabidopsis and monocot rice plants. In contrast, Ubi:CaPUB1 progeny exhibited phenotypes markedly tolerant to prolonged low temperature ($4^{\circ}C$) treatment, compared to those of wild-type plants, as determined by survival rates, electrolyte leakage, and total chlorophyll content. Cold stress-induced marker genes, including DREB1A, DREB1B, DREB1C, and Cytochrome P450, were more up-regulated by cold treatment in Ubi:CaPUB1 plants than in wild-type plants. These results suggest that CaPUB1 serves as both a negative regulator of the drought stress response and a positive regulator of the cold stress response in transgenic rice plants. This raises the possibility that CaPUB1 participates in the cross-talk between drought and low-temperature signaling pathways.

• Journal of Plant Biotechnology
• /
• 제5권2호
• /
• pp.87-93
• /
• 2003

Brachiaria (Poaceae) is the most important forage genus for cattle production in Brazil. The genetic breeding of this genus is limited by the incompatibility among species, differences in ploidy level and the natural cloning of plants by apomixis (Valle and Miles 1992). However, plant regeneration via tissue culture methods and genetic engineering provide an opportunity to introduce new characteristics in plants of this genus. We have developed methods for the 'genetic modification of Brachiaria brizantha cv. Marandu via biolistic transformation. A higher number of shoots was obtained with 4 mg/L 2.4-diclorophenoxyacetic acid and 0.2 mg/L benzylaminopurine in calli induction medium and 0.1 mg/L naphtaleneacetic acid and 4.0 mg/L kinetin in shoot regeneration medium. A selection curve for mannose was determined to use phospho mannose isomerase (PMI) gene of Escherichia coli as a selection marker. Calli formation was inhibited from 5 g/L mannose, even in the presence of sucrose while calli that were formed in the presence of mannose failed to develop embryos showing that PMI gene can be used for selection of transformants of this grass. Different promoters were tested to evaluate the efficiency based on the detection of the GUS gene expression (Jefferson et al. 1987). The monocot promoters, act1-D and ubi-1, resulted in higher expression levels than dicot promoters, ubi-3 and act-2, or the CaMV35S and CVMV promoters.

• 식물조직배양학회지
• /
• 제26권1호
• /
• pp.41-47
• /
• 1999

토마토의 genomic DNA library로부터 분리한 tPALl, tPAL4유전자의 염기서열을 분석하여 tPAL5 유전자와 비교 분석한 결과는 다음과 같다. tPAL5 유전자는 722개의 아미노산과 710 bp의 intron을 가지고 있으나 tPALl은 intron을 가지고 있지 않으며 또한 tPAL5 유전자와 비교하여 249개의 짧은 polypeptide를 가지고 있었다. tPAL4유전자인 경우 357개의 아미노산과 305bp의 intron을 가지고 있었다. tPAL 효소간의 아미노산 homology는 tPAL1유전자와 tPAL4 유전자간은 87.2%, tPALl과 tPAL5는 85.3%, tPAL4 와 tPAL5 는 91.4%의 homology를 보였다. 또한, tPALl, tPAL4 유전자는 정상적인 polypeptide를 가지는 tPAL5유전자와 비교하여 비정상적인 stop codon을 가진 짧은 polypeptide로 구성되어 있었다. 다양한 식물 종으로부터 분리된 PAL유전자의 염기서열을 비교한 결과 토마토 (Lycopersicon esculentum), 감자 (Solanum tuberosum), 고구마 (Ipomoea batatas)간의 유연관계과 높았으며, parsley (Petroselinum crispum), bean (Phaseolus vulgaris), pea (Pisum sativum), alfalfa (Medicago sativa) 등이 각각 서로간에 유연관계가 높았다. 또한, 토마토에서 분리한 family내에서 tPAL4와 tPAL5 유전자는 homology가 매우 높았고 (93.0%), tPAL1와 tPAL4유전자 사이는 다소 낮았으며 (84.4%), 특히 tPAL4는 감자의 PAL 유전자와 매우 높았다 (90.6%).

• 한국토양비료학회지
• /
• 제33권4호
• /
• pp.247-252
• /
• 2000

카트뮴은 잎과 엽록체내 폴리아민함량을 증가시키지만 틸라코이드와 광포집체II내에서는 증가효과가 없었다. 카드뮴에 의해 새로 생합성된 폴리아민은 스트로마공간상에 분포하는 것으로 보였다. 폴리아민은 이미 포화되더라도 틸라코이드막에 결합하지는 않는 것으로 밝혀졌으며 엽록체내 putrescine과 spermine은 잎세포내에서 보다 각각 36배와 20배 적었던 반면 agmatine은 3.7배 적었다. 카드뮴의 산소방출 억제효과는 0.2mM spermine 첨가로 현저히 완화되었다. 폴리아민은 또한 시금치 틸라코미드에서 0.5mM 농도이하에서 산소방출을 촉진하였다. 이러한 촉진효과는 동일농도에서 단자엽보다는 쌍자엽에서 2배정도 높았다. 더욱이 쌍자엽 밀에서 상승효과는 putrescine보다는 agmatine처리에서 오히려 낮았다. 이러한 결과로부터 단자엽과 쌍자엽 식물간에 폴리아민의 산소방출 과정에서 다른 효능을 보임을 알 수 있었다.

• Weed & Turfgrass Science
• /
• 제6권3호
• /
• pp.212-221
• /
• 2017

방선균 G-0299의 살초특성을 확인하여 천연 제초제 후보소재로서의 가능성을 검토하고자 수행하였다. 선발된 방선균 G-0299는 바랭이에서만 살초력이 발휘되었을 뿐만 아니라 경엽처리 효과, 엽록소 함량 등의 생리 생화학적인 반응에서 광조건에서만 발현되는 독특한 살초특성을 보였다. 방선균 G-0299 배양 여액 농축 시료를 처리했을 때 속효성이며, 고사 또는 백화현상이 발현되는 등의 특징으로부터 광합성 저해 또는 protox 저해 제초제와 비슷한 작용기전을 갖고 있을 가능성을 유추해 볼 수 있겠으나 오직 바랭이에서만 살초력이 발휘되는 특이한 현상을 고려하면 상관성을 설명하기는 곤란하였다. 따라서 천연 제초활성 후보소재 방선균 G-0299의 보다 상세한 살초기 전에 관해서는 추가 연구를 통해 구명되어야 할 것이다.

• 생명과학회지
• /
• 제21권2호
• /
• pp.328-333
• /
• 2011

동물호르몬으로 알려진 멜라토닌(melatonin)은 동물뿐 아니라 고등 식물을 포함한 다양한 생명체에 존재한다. 식물에서는 쌍떡잎 식물과 외떡잎 식물에 멜라토닌이 널리 존재하며 일부 약용 식물에는 다량으로 함유되어 있지만 아직 그 생합성 과정과 생리학적 기능은 확립되지 않았다. 본 연구에서는 reverse phase HPLC 분석을 통하여 이제까지 분석이 이루어지지 않았던 여러 제비꽃속(Viola) 식물들에 멜라토닌이 고르게 분포한다는 사실을 확인하였다. 그 다음 제비꽃속 식물들의 잎 절편을 배양하며 멜라토닌의 최초 전구체로 제안된 tryptophan (Trp)과 이의 탈카르복시화(decarboxylation) 중간산물인 tryptamine (TAM)을 공급하였다. 그 결과 Trp을 공급하면 멜라토닌 생성에 영향을 미치지 않았지만 TAM을 공급한 경우에는 멜라토닌의 함량이 증가하였다. TAM은 Trp에서 유래하므로 Trp-TAM 경로가 제비꽃속 식물에도 존재하는 것으로 판단되며, Trp 공급이 멜라토닌 함량에 영향을 미치지 않는 결과는 Trp을 TAM으로 전환하는 탈카르복시화 과정이 식물 멜라토닌 생합성 과정의 속도결정 단계일 것이라는 가설을 지지하는 것으로 사료된다.

• Molecules and Cells
• /
• 제27권4호
• /
• pp.467-473
• /
• 2009

Our previous study suggested that OsBWMK1, a gene which encodes a member of the rice MAP kinase family, generates transcript variants which show distinct expression patterns in response to environmental stresses. The transcript variants are generated by alternative splicing and by use of alternative promoters. To test whether the two alternative promoters, pOsBWMK1L (promoter for the OsBWMK1L splice variant) and pOsBWMK1S (promoter for the OsBWMK1S splice variant), are biologically functional, we analyzed transgenic plants expressing GUS fusion constructs for each promoter. Both pOsBWMK1L and pOsBWMK1S are biologically active, although the activity of pOsBWMK1S is lower than that of pOsBWMK1L. Histochemical analysis revealed that pOsBWMK1L is constitutively active in most tissues at various developmental stages in rice and Arabidopsis, whereas pOsBWMK1S activity is spatially and temporally restricted. Furthermore, the expression of pOsBWMK1S::GUS was upregulated in response to hydrogen peroxide, a plant defense signaling molecule, in both plant species. These results suggest that the differential expression of OsBWMK1 splice variants is the result of alternative promoter usage and, moreover, that the mechanisms controlling OsBWMK1 gene expression are conserved in both monocot and dicot plants.