UV-B irradiation enhances the accumulation of beneficial glucosinolates induced by melatonin in Chinese kale sprout

Cruciferous sprout is a new form of vegetable product rich in bioactive compounds,especially glucosinolates.Previous studies have focused on increasing the accumulation of glucosinolates in cruciferous sprouts by applying different chemical regulators,with a particular focus on their contribution to nutritional quality and health benefits.Nevertheless,the effects of melatonin and UV-B irradiation on glucosinolate biosynthesis remain unclear.In this study,it was found that changes in melatonin concentrations significantly affected the contents of individual as well as total aliphatic and indolic glucosinolates.The 5μmol·L^(-1)melatonin was decided as the optimum concentration that could increase the content of beneficial glucosinolates including glucoraphanin and 4-methoxy glucobrassicin in Chinese kale sprouts.Notably,the enhancement of glucosinolate accumulation by melatonin treatment could be further amplified by UV-B irradiation.Furthermore,our results showed that R2R3-MYB transcription factor BoaMYB28 and BoaMYB51,which are central regulators of aliphatic and indolic glucosinolate biosynthesis respectively,were both involved in the regulation of glucosinolate biosynthesis by melatonin and UV-B irradiation.Additionally,the expression of glucosinolate biosynthetic genes,including BoaCYP79F1,BoaCYP83A1,BoaSUR1,BoaUGT74B1,BoaCYP79B2,BoaCYP79B3,and BoaCYP83B1 participated in the formation of core structures and BoaFMOGS-OX5,BoaAOP2,BoaCYP81F2,and BoaIGMT1 involved in the sidechain modification of aliphatic and indolic glucosinolate,was regulated by melatonin or UV-B irradiation.Taken together,these findings provide a potential strategy for improving the nutritional quality and resistance of Chinese kale sprouts.

Effect of Different Irrigation Maximums on Accumulation and Distribution of Material in Chinese Kale

[Objective] The aim was to explore effects of soil moisture on dry matter accumulation and distribution and growth of kai-lan. [Method] In the context of the same irrigation frequency, the influence of irrigation maximum was researched on growth rate, net assimilation rate, and dry matter distribution of kai-lan. [Result] The results showed that regulation on soil moisture extremely significantly affected accumulation of photosynthate. When soil moisture was insufficient, the growth term from seedling to mature extended and growth rate declined sharply. Besides, the growth term was of extremely significant negative correlation with growth rate. Meanwhile,leaf assimilation rate decreased considerably. For example, when soil moisture was65%, distribution of dry matter in plant organs tended to be rational. [Conclusion]Deficit irrigation would significantly lower growth rate, and improve dry matter distribution in organs and economic yield and quality of kai-lan.

Effect of Different Irrigation Maximums on Absorption and Utilization of Water in Chinese Kale

[Objective] This study was conducted to investigate the effect of soil moisture on the growth and water utilization of Chinese kale. [Method] The law of water absorption and utilization of Chinese kale was researched under the same irri- gation frequency and different irrigation maximums. [Result] Soil water deficit re- duced water contents in plants in seedling stage and in plants and various organs in maturation stage; water consumption of individual plant was the lowest in 55% treatment of soil A and 45% treatment of soil B, which showed the values of 2.244 and 2.235 L/plant, respectively, and saved water by 23.91% and 21.14% compared with CK; water use efficiencies of soil A with a water content of 55% and soil B with a water content of 35% were the highest, i.e., 6.043 and 5.958 g/L, which were higher than that of CK by 20.09% and 41.72%, respectively; and regulated deficit irrigation also improved irrigation water productivity, and the two kinds of soil both showed in 75% treatments the highest irrigation water productivities, i.e., 40.44 and 40.49 g/L, which were higher than that of CK by 5.64% and 13.39%, respec- tively. [Conclusion[ Controlling irrigation maximum could save water consumed by Chinese kale, improve water use efficiency and improve yield and quality.

Monosomic Addition Lines of Flowering Chinese Cabbage(B.campestris L.ssp.chinensis var.parachinensis L.H.Bailey)-Chinese Kale(B.oleracea L.var.alboglabra L.H.Bailey)

Interspecific alien addition lines have played significant roles in gene mapping, intergenomic gene transfer and chromosomal homoeological identification between closely related species. Selection of alien addition lines was conducted by karyotype analysis and morphological observation with the reference of parents. Triploid interspecies hybrid （AAC, 2n = 3x = 29） was obtained from Brassica campestris ssp. chinensis var. parachinensis Qinglu 9601 （tetraploid, AAAA, 2n = 4x = 40） x B. oleracea var. alboglabra Baihua 9705 （diploid, CC, 2n = 2x = 18） by immature hybrid embryo culture in vitro. Five different alien monosomic addition lines （AA ＋ C2, AA ＋ C3, AA ＋ C4, AA ＋ C6, AA ＋ C7） were obtained from the backcross progenies of AAC x AA. Each alien monosomic addition line has some specific morphological characters. It is feasible to obtain alien addition lines from the progenies of AAC × AA by karyotype analysis and morphological observation based on the reference of parents

Construction of Plant Antisense Expression Vector with Defective in Anther Dehiscence1 Gene Fragment of Chinese Kale

A pair of primers was designed according to the reported conserved sequence of the defective in anther dehiscencel （DAD1） gene ofArabidopsis thaliana and Brassica rapa. A 558 bp long fragment was amplified from genomic DNA of Chinese kale, showing more than 88% identity with the known DAD1 nucleotide sequence and no intron. The reverse of the amplified fragment was ligated to the downstream of the CaMV35S promoter in the plant expression vector pBIl21. Antisense expression vector pBII21-DAD1F was constructed with DAD1 fragment of Chinese kale, and was transferred into Agrobacterium tumefaciens, which will be used in the transformation to create male sterile materials of Chinese kale.

Molecular Cloning and Expression Analysis of the ζ-Carotene Desaturase Gene in Chinese kale(Brassica oleracea var.alboglabra Bailey)

ζ-Carotene desaturase(ZDS)is an important enzyme in carotenoid biosynthesis.Here,the Brassica oleracea var.alboglabra ZDS(Boa ZDS)gene was cloned from Chinese kale via reverse transcription-polymerase chain reaction(RT-PCR)and deposited in Gen Bank(accession number KY662297).The Boa ZDS gene contains an open reading frame of 1 686 bp that encodes a 561-amino acid protein.Sequence analysis indicates that the ZDS protein is apparently conserved during plant evolution and is most closely related to B.oleracea var.capitata and B.rapa.The promoter sequence of the Boa ZDS gene was predicted to harbor several cis-acting elements that are related to light and phytohormone responses.Semiquantitative RT-PCR analysis showed that Boa ZDS expression varied among different developmental stages and organs.Relative ZDS expression remained stable during germination and seedling stages and rapidly increased at the mature leaf stage.The leaves showed the highest ZDS expression levels compared to the other organs.ZDS expression decreased in all flower tissues during blooming.The fused protein of Boa ZDS was obtained by prokaryotic expression.Heterologous expression of Boa ZDS in Escherichia coli confirmed that Boa ZDS encodes a functionalζ-carotene desaturase that increases β-carotene accumulation in E.coli cells harboring a β-carotene-producing plasmid.The findings of the present study provide a molecular basis for the elucidation of ZDS gene function in Chinese kale.

Germplasm Diversity of Chinese Kale in China

Chinese kale is an important vegetable crop in China, especially in South China where the majority of varieties are grown. It originated in South China and spread throughout Southeast Asia thereafter. Chinese kale can be classified into two types according to whether the petals are white or yellow. There are also three main cultivated types based on the edible organs, including the stalk and leaf type, the stalk type,and the leaf type. Two primary types have also been defined based on stalk color, including green stalks and red stalks. They are also cultivated based on the type of stalk, including main stalk and lateral stalk types. Significant differences have also been observed in glucosinolate content among the varieties, and a 40-fold difference in neoindle-3-methyl glucosinolate was detected across the cultivars.

Effects of glucose and gibberellic acid on glucosinolate content and antioxidant properties of Chinese kale sprouts

Glucosinolates, anthocyanins, total phenols, and vitamin C, as well as antioxidant capacity, were investigated in Chinese kale sprouts treated with both glucose and gibberellic acid（GA_3）. The combination of 3%（0.03 g/ml） glucose and 5 μmol/L GA_3 treatment was effective in increasing glucosinolate content while glucose or GA_3 treatment alone did not influence significantly almost all individual glucosinolates or total glucosinolates. The total phenolic content and antioxidant activity of Chinese kale sprouts were enhanced by combined treatment with glucose and GA_3, which could be useful in improving the main health-promoting compounds and antioxidant activity in Chinese kale sprouts.