Metabolic Engineering of Indole Glucosinolates in Chinese Cabbage Plants by Expression of Arabidopsis CYP79B2, CYP79B3, and CYP83B1

Zang, Yunxiang,Lim, Myungho,Park, Beomseok,Hong, Seungbeom,Kim, Doohwan Korean Society for Molecular Biology 2008 Molecules and cells Vol.25 No.2

Indole glucosinolates (IG) play important roles in plant defense, plant-insect interactions, and stress responses in plants. In an attempt to metabolically engineer the IG pathway flux in Chinese cabbage, three important Arabidopsis cDNAs, CYP79B2, CYP79B3, and CYP83B1, were introduced into Chinese cabbage by Agrobacterium-mediated transformation. Overexpression of CYP79B3 or CYP83B1 did not affect IG accumulation levels, and overexpression of CYP79B2 or CYP79B3 prevented the transformed callus from being regenerated, displaying the phenotype of indole-3-acetic acid (IAA) overproduction. However, when CYP83B1 was overexpressed together with CYP79B2 and/or CYP79B3, the transformed calli were regenerated into whole plants that accumulated higher levels of glucobrassicin, 4-hydroxy glucobrassicin, and 4-methoxy glu-cobrassicin than wild-type controls. This result suggests that the flux in Chinese cabbage is predominantly channeled into IAA biosynthesis so that coordinate expression of the two consecutive enzymes is needed to divert the flux into IG biosynthesis. With regard to IG accumulation, overexpression of all three cDNAs was no better than overexpression of the two cDNAs. The content of neoglucobrassicin remained unchanged in all transgenic plants. Although glucobrassicin was most directly affected by overexpression of the transgenes, elevated levels of the parent IG, glucobrassicin, were not always accompanied by increases in 4-hydroxy and 4-methoxy glucobrassicin. However, one transgenic line producing about 8-fold increased glucobrassicin also accumulated at least 2.5 fold more 4-hydroxy and 4-methoxy glucobrassicin. This implies that a large glucobrassicin pool exceeding some threshold level drives the flux into the side chain modification pathway. Aliphatic glucosinolate content was not affected in any of the transgenic plants.

Glucosinolate Enhancement in Leaves and Roots of Pak Choi (Brassica rapa ssp. chinensis) by Methyl Jasmonate

Yunxiang Zang,Hao Zhang,Linghui Huang,Fang Wang,Fei Gao,Xishan Lv,Jing Yang,Biao Zhu,홍승범,Zhujun Zhu 한국원예학회 2015 Horticulture, Environment, and Biotechnology Vol.56 No.6

Glucosinolates have attracted considerable attention in the past several decades because of their involvement in pathogen and insect resistance of Brassicaceae as well as anti-inflammatory and anti-oxidation activity in humans. Methyl jasmonate (MeJA) treatment generally increases the levels of indole and aromatic glucosinolates; however, the time course of MeJA effects on the levels of individual glucosinolates in different pak choi cultivars has not been studied. Here, we found that foliar MeJA application increased accumulation of indole glucosinolates in both leaves and roots of four cultivars. However, roots accumulated much higher levels of indole glucosinolates and, compared to leaves, showed a delayed response to MeJA in terms of indole glucosinolate accumulation in all four cultivars. Individual indole glucosinolate levels in roots differed depending on the sampling time in different cultivars. The level of neoglucobrassicin steadily increased over 72 h. Glucobrassicin was induced in leaves of SHQ and HZYDE, and in roots of three cultivars, whereas 4-methoxyglucobrassicin was induced only in roots. Aromatic glucosinolate enrichment occurred only in roots. Aliphatic glucosinolates were detected only in the leaves but not in roots, accumulating to comparable levels as in untreated controls. These results suggest that exogenous MeJA-mediated signal transduction did not immediately lead to biosynthesis of aliphatic and aromatic glucosinolates but did induce increased accumulation of indole glucosinolates in pak choi. Individual glucosinolate accumulation profiles were different depending oncultivars.

Accumulation of Glucosinolates and Nutrients in Pakchoi (Brassica campestris L. ssp. chinensis var. communis) Two Cultivar Plants Exposed to Sulfur Deficiency

Keling Hu,Zhujun Zhu,Yunxiang Zang,Syed Azhar Hussain 한국원예학회 2011 Horticulture, Environment, and Biotechnology Vol.52 No.2

To understand how sulfur nutrition affects the quality and yield of vegetable plants, we have grown two cultivars of pakchoi (Brassica campestris L. ssp. chinensis var. communis cv. Shang Hai Qing and You Dong Er) hydroponically in nutrient solution supplied with two levels of sulfur (0.0558 mM as sulfur deficiency and 1.0058 mM as sulfur sufficiency, respectively) for three weeks and their growth, nutrient uptake and glucosinolate content under these two sulfur conditions were investigated. The results showed that plant growth of both the cultivars was inhibited by sulfur deficiency. The concentrations of nitrogen and magnesium in shoots of both the cultivars were increased notably under sulfur deficiency, but there was no significant change in concentrations of sulfur, potassium and calcium. Moreover, sulfur deficiency increased phosphorus uptake in You Dong Er but not in Shang Hai Qing. In Shang Hai Qing sulfur deficiency reduced the content of all individual and total glucosinolates, while in You Dong Er this was also the case for most individual and total glucosinolates. However, in You Dong Er the total aliphatic glucosinolate concentration was not significantly influenced but the concentrations of individual aliphatic glucosinolates-glucoalyssin and gluconapin were in contrast increased under sulfur deficiency. Our data show that sulfur deficiency will decrease the yield and deteriorate the quality of pakchoi vegetable by reducing its growth and the contents of nutrients and glucosinolates. In addition, there was a significant genotypic variation in the composition and content of glucosinolates between these two pakchoi cultivars when exposed to sulfur deficiency.

Exogenous 5-aminolevulinic acid promotes plant growth and salinity tolerance of grape rootstocks in coastal areas

Zheng Weiwei,Tian Yuting,Shi Haili,Chen Miaomiao,Hong Seungbeom,Xu Kai,Cheng Jianhui,Zang Yunxiang 한국원예학회 2023 Horticulture, Environment, and Biotechnology Vol.64 No.2

Salinity stress is a key factor aff ecting grape production in coastal areas. Two grape rootstock cultivars, ‘Beta’ (sensitive to salt stress) and ‘3309 C’ (resistant to salt stress), were used to investigate the physiological role of 5-aminolevlinic acid (5-ALA) in salinity tolerance. Functional capacities in the rhizosphere, leaf phenotype, photosynthetic parameters, antioxidant enzymes activities and certain physiological indexes were determined after treatment with seawater or seawa- ter followed by 100 mg/L 5-ALA application. The results showed that the functional capacities of the rhizosphere were distinct between the two management regimes. Microbial biomass and soil enzyme activities were reduced by salinity but promoted by 5-ALA. Salinity also suppressed the overall plant growth, leaf chlorophyll content, photosynthetic rate, maxi- mal photochemical effi ciency (Fv/Fm), photochemical quenching (qP), electron transport rate (ETR), root activity, ATP content, ATPase activity, and activities of the antioxidant enzymes ascorbate peroxidase (APX), peroxidase (POD), cata- lase (CAT), and superoxide dismutase (SOD) in both cultivars. Although plant growth, chlorophyll content, and activities of antioxidant enzymes in Beta were decreased to a greater extent than those in 3309 C under salinity stress, exogenous application of 5-ALA signifi cantly improved plant growth along with enhancement of all the above photosynthetic param- eters and activities of the four antioxidant enzymes in both cultivars. Seawater treatment alone signifi cantly increased non- photochemical quenching (NPQ), relative electrical conductivity (REC), and malondialdehyde (MDA) contents in leaves, especially for Beta. However, 5-ALA treatment decreased the levels of NPQ, REC, and MDA, but increased ATP content and ATPase activity in roots and leaves of both cultivars. Thus, application of 5-ALA would be benefi cial to improve the salt tolerance of grape rootstocks grown in coastal areas.