The effects of exogenous sodium nitroprusside (SNP, nitric oxide donor) on the growth, yield, photosynthetic characteristics, and antioxidant enzyme activity of kimchi cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) was studied under the low temperature conditions. Kimchi cabbages were treated with SNP of three concentrations (7.5, 15, 30 mg·L-1) for three times at four-day intervals and exposed to low temperature (16/7°C) stress for seven days. SNP treatment induced increases of net photosynthetic rate (Pn), stomatal conductance (Gs), intracellular CO2 concentration (Ci) and transpiration rate (Tr) under the stress condition with the highest level after the third treatment. The contents of malondialdehyde (MDA) and H2O2 were significantly lower in the treatment of SNP compared to the non-treated control. The activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), increased in treated plants by up to 38, 187, 24 and 175%, respectively compared to the non-treated control. SNP-treated and untreated plants had similar growth characteristics. Compared to the control group, SNP-treatment increased fresh weight and leaf area by 5%. Overall, our findings suggest that the application of sodium nitroprusside to the leaves contributes to reducing physiological damage and enhancing the activities of antioxidant enzymes, thereby improving low temperature stress tolerance in kimchi cabbage.

This experiment was conducted to assess the high antioxidant activity varieties of Chinese cabbage (Brassica rapa L. ssp. pekinensis) from the 55 accessions. The antioxidant activity of Chinese cabbage were determined by the TPC, TFC, DPPH, ABTS, and chlorophyll, carotenoid contents. The TPC and TFC showed a range of 1.21~4.61 mg GAE/g DW, 0.18~3.09 mg CE/g DW. The DPPH and ABTS assay were in the range of 0.65~4.36 and 1.42~6.91 mg ascorbic acid equivalent (ASCE)/g DW, respectively. The UPLC analysis was performed quantitatively to identify chlorophyll and carotenoid in the Chinese cabbage extract. The levels of the total chlorophyll and total carotenoid were 86.60~1,235.91, and 75.86~490.11 μg/g, respectively. The comprehensive differences in the total and individual chlorophyll contents have also been observed among different varieties. These results will be valuable as basic data for the standardization of Chinese cabbage.

본 연구는 정식 후 토양의 수분 함량에 따른 배추의 생장과 토양 수분에 따른 배추의 생리 반응 모델 개발을 위한 유효 매개변수를 알아보고자 수행되었다. 처리는 5개 수준으로 각각 0, 200, 300, 400 및 500mL/d/ plant로 매일 1회 관수하여 토양 수분 함량 차이로 구분하였다. 토양수분과 기공전도도를 정식 후 10일부터 6일 간격으로 총 5회 측정하였으며(단, 0과 200mL/d/plant 처리구는 총 3회 측정), 광합성기구 활성을 알아보고자 정식 후 25일에 충분히 관수된 처리구(500mL/d/plant)와 결핍 처리구(0mL/d/plant)에서 이산화탄소 포화 곡선을 작성하였고, 정식 후 38일에 생장을 조사하였다(단, 관수 량 처리구 0과 200mL/d/plant는 위조되어 정식 후 29일에 생장 조사함). 토양수분과 배추의 기공전도도는 밀접한 관계가 있었으며(r2=0.999), 직선의 정의 상관관계로 y = 6097.4x − 4.2984였다. 충분히 관수된 배추의 이산화 탄소 포화곡선은 정상적인 포화 곡선을 보였으나, 토양 수분이 극도로 결핍된 배추는 체내로 이산화탄소가 확산 되어 들어가지 않으며, 광합성 속도도 약 6.5μmol·m-2·s-1 미만으로 급격히 감소하였다. 충분히 관수된 처리구 (500mL/d/plant)에 비하여 토양 수분 결핍구(0mL/d/plant 처리)에서는 약 6.8배 이상 건물생산량이 감소하였다. 그리고 토양의 수분 함량에 따라 엽면적 지수가 로그함수적(y = 16.573 + 3.398 ln x)으로 증가하였고, 결정 계수 r2=0.913로 높은 상관 관계가 있었다. 결과적으로, 정식 초기의 토양 수분 함량이 결핍되면 배추의 생장이 지연 되며, 광합성 속도와 기공전도도가 낮아지는 것으로 밝혀졌다. 또한, 토양수분 함량과 배추 생장 반응 모델을 기공전도도와 엽면적 지수를 변수로 활용하면 정확도가 우수한 모델을 개발할 수 있을 것으로 기대된다.

This study examined the total glucosinolate (GSL) and isothiocyanate (ITC) contents according to different processing conditions; fresh Kimchi cabbage (Brassica rapa L. ssp. pekinensis), salted Kimchi cabbage and kimchi (storage temperature 4℃ and 20℃) using two different cultivars (Bomatnorang and Chunkwang). Four GSL peaks representing gluconapin, glucobrassicanapin, glucobrassicin and 4-methoxyglucobrassicin were detected in Kimchi cabbage by HPLC and HPLC/MS analysis. The total GSL contents of fresh Kimchi cabbage of Bomatnorang and Chunkwang were 21.37±1.06 μg/g dry weight (DW) and 20.96±3.33 μg/g DW, respectively. After salting, the total GSL contents of salted Kimchi cabbage decreased by 39% and 52% in Bomatnorang and Chunkwang, respectively. Finally, the total GSL contents of kimchi after storage at 20℃ decreased by 83% and 56% in Bomatnorang and Chunkwang, respectively. The extracted ITC contents were analyzed by GC/MS. Three ITC peaks were detected in Kimchi cabbage representing 2-phenylethyl ITC, 3-butenyl ITC and 4-pentenyl ITC. The 2-phenylethyl ITC levels increased during the salting process but this generally fell during storage at 20℃ as kimchi. The 3-butenyl ITC levels of Kimchi cabbage according to processing decreased rapidly due to salting and then decreased slowly during storage as kimchi. The 4-pentenyl ITC of Kimchi cabbage was lost during the salting process. The results for the change in GSL and ITC contents during the kimchi making process will be used in the food industry.

The TIFY family is composed of a plant-specific group of genes with diversity of functions. This family represents four subfamily of proteins viz. ZML, TIFY, PPD and JASMONATE ZIM-domain (JAZ) proteins. TIFY proteins especially, JAZ proteins have been reported to perform different biological processes, such as developmental and stresses and hormone responses in Arabidopsis and rice. However, there is no information about this family genes in Brassicaceae. This study identifies 36 TIFY genes in Brassica rapa, an economically important crop species from this family. An extensive in silico analysis through phylogenetic grouping, protein motif organization and intron-exon distribution also confirmed 4 subfamilies of BrTIFY proteins. Out of 35 BrTIFY genes, we identified 21 under JAZ subfamily besides 7 TIFY, 6 ZML and 2 PPD. An extensive expression profiling of 21 BrTIFY JAZs both in tissues and organs of B. rapa revealed differential expression patterns. Almost all the BrTIFY JAZs predominantly expressed in leaves and flower buds. Besides, in a flower stage specific expression analysis we observed 14 BrTIFY JAZs with constitutive expression patterns. This indicates BrTIFY proteins have a strong involvement in the development of B. rapa flowers. Our protein interaction study also reveals the strong association of these proteins with the fertility and defense processes of B. rapa. To elucidate the stress responsiveness of BrTIFY genes, we analyzed the low temperature-treated whole-genome microarray data set and found almost all the BrTIFY JAZs were having variable transcript abundance in two contrasting inbred lines of B. rapa. Subsequently, all 21 BrTIFY JAZs were validated in response to cold stress in the same two lines via qPCR, where 9 genes were found to show up- regulation. And, a high and differential qPCR expression pattern of all the BrTIFY JAZs was also recorded against JA. Additionally, BrTIFY JAZs were tested against salt, drought, Fusarium, ABA and SA treatments and a considerable number of genes were found to be induced. The extensive annotation and transcriptome profiling reported in this study will be useful for understanding the involvement of TIFY genes in stress resistance and different developmental functions, which ultimately provides the basis for functional characterization and exploitation of the candidate genes for genetic engineering of B. rapa.

Shaggy-like kinases (SKs), also known as Glycogen synthase kinase 3 (GSK3) proteins, play many important roles in cellular signaling in animals, fungi and amoebae. In particular, SKs participate in key developmental signaling pathways and also regulate the cytoskeleton. SKs -encoding genes are also present in all land plants and in algae, raising questions about possible ancestral functions in eukaryotes. Unlike in animals and Dictyostelium, land plant SKs are encoded by relatively large multi-gene families whose members share high sequence similarity. Along with the studied 10 ASKs (Arabidopsis shaggy-like kinases) indicate that plant SK proteins are actively implicated in hormonal signalling networks during development as well as in biotic and abiotic stress responses. In this study, 18 BrSKs are identified from Chinese cabbage, and they are classified into four groups according to the classification of Arabidopsis. The characterization, classification, gene structure and phylogenetic construction of BrSK proteins are performed. Distribution mapping shows that BrSKs are absented in A02 and A10 chromosome. 8 orthologous gene pairs are shared by Chinese cabbage and Arabidopsis. The expression patterns of BrSK genes exhibit differences in five tissues based on RNA-seq data in public data base. Specially, BrSKβ-1 and BrSKβ-2 show floral buds specifically expressed, which indicate that BrSKβ may play a key role during flower or pollen development. We deomonatrated that suppresion of Arabdiopsis orthology of BrSKβ impaired the late pollen in Arabidopsis plants. Taken together, our analyses provided insights into the characterization of the BrSK genes in Chinese cabbage, providing foundation of further functional studies of those genes. [This work was supported by a grant from the Next-Generation BioGreen 21 Program (the Next-Generation Genomics Center No. PJ008118), Rural Development Administration, Republic of Korea]

As the drought is getting worse, Lot of studies related to drought stress in plant have been conducted. Recently whole genome sequencing of Brassica rapa ssp which is important vegetable crop to East Asians has been completed to enable Omic research. It is known that the drought damages occur in the early stage of plant development. Here, we performed shotgun proteomics analysis of B. rapa to observe the morphological characters, monitor the expression patterns of the identified proteins during drought stress, and detect the proteins related to drought stress. The three week old B. rapa grown in density of single plant in a single pot were used. Drought stress were treated as that a single plant in soil was removed from the pot and the plant with soil was exposed to air and light without watering. Leaves were immediately harvested before drought treatment, 24hr after drought treatment, and 48hr after drought treatment. The protein expression patterns were monitored by a quantitative shotgun proteomics analysis. Extracted proteins were separated in 1D-SDS-PAGE then the gel sliced into seven pieces. Chopped gels were ingel-digested. Peptides were assigned to mass spectrometry (Q-Exactive). The ms/ms spectra were analyzed through Proteome Discoverer. By combining all of the identified proteins in the seven sliced gel samples, total B. rapa proteome reference map was completed. Protein expression patterns were investigated by comparing the quantity of protein. With shotgun proteomic approach, we evaluated the changes in the quantity and finally discovered the candidate proteins related with drought stress.

This study investigated the quality characteristics between spring cultivars of Kimchi cabbage(Brassica rapa L. ssp. pekinesis). We measured the weight, length, width, formation index, midrib thickness and moisture contents of fresh Kimchi cabbage for characteristics of growth. And we analyzed the free sugar, amino acid, organic acid, mineral, pectin and cellulose contents of fresh Kimchi cabbage. The hardness and firmness were measured for texture of fresh Kimchi cabbage. The weight of 'K-power' cultivar was the highest than other cultivars. The ‘Jeongsang’ cultivars was the thinnest midrib thickness in cultivars, but it was not significantly different. The free sugar levels of spring cultivars was the highest in ‘Chunkwang’. Malic acid content of ‘Jeongsang’ was significantly different among spring cultivars. Also amino acid content of ‘K-power’ and ‘Chunkwang’ were significantly different among spring cultivars Mineral content in ‘K-power’ and ‘Bomaknorang’ were greater than that of other cultivars. Especially Na, Ca and Mg contents of ‘K-power’ and ‘Bomaknorang’ were higher four times than that of other cultivars. Pectin content of ‘Jeongsang’ was higher than that of other cultivars, but it was not significantly different. Hardness and Firmness were not significantly different among spring cultivars.