ABSTRACT
Low temperature is one of the environmental factors that restrict the growth and geographical distribution of Brassica. To investigate the effects of exogenous calcium and calcium inhibitor on the ability of winter turnip rapeseed (Brassica rapa L.) to withstand low temperatures (4â), we used a strong cold-resistant variety Longyou 7 (L7) and a weak cold-resistant variety Longyou 99 (L99) as the materials. The seedlings were treated with CaCl2 (20 mmol·L-1) and calcium inhibitor LaCl3 (10 mmol·L-1) at 0 h (CK), 6 h, 12 h, 24 h and 48 h after 4â treatments. Physiological characteristics, Ca2+ flux and Ca2+ concentration in roots after treatments were analyzed. Results illustrated that under 4â treatment, activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased by both CK and exogenous CaCl2 treatments. Contents of soluble protein (SP) and proline (Pro) increased, while contents of malondialdehyde (MDA) decreased, resulting in reduced membrane lipid peroxidation. But enzyme activity decreased and MDA content increased following treatment with exogenous LaCl3. The rate of Ca2+ flow showed a higher uptake in L7 roots compared with L99. L99 showed Ca2+ efflux with a rate of 30.21 pmolâ§cm-2â§s-1, whereas L7 showed short efflux then returned to influx. Calcium ion content in roots decreased in both cultivars after CaCl2 treatment. Results of RNA-seq revealed that genes were differentially expressed in response to low temperatures, hormones, photosystem II, chloroplasts, DNA replication, ribosomal RNA processing, and translation. This study found significant expression genes related to cellular signal transduction (MAPK signaling pathway) and material metabolism (nitrogen metabolism, glycerol ester metabolism).It was also analyzed by WGCNA that two modules had the strongest correlation with physiological indicators. Eight candidate genes were identified among MAPK signaling pathway and the two modules.
Subject(s)
Brassica rapa , Calcium , Brassica rapa/drug effects , Brassica rapa/genetics , Brassica rapa/physiology , Calcium/metabolism , Cold Temperature , Seedlings/drug effects , Seedlings/genetics , Seedlings/physiology , Plant Roots/drug effects , Plant Roots/metabolism , Plant Roots/genetics , Cold-Shock Response/drug effects , Gene Expression Regulation, Plant/drug effects , Calcium Chloride/pharmacologyABSTRACT
The codeinone reductase gene (cor) and the berberine bridge enzyme gene (bbe) were cloned from young leaf of opium poppy(Papaver somniferum L) by RT-PCR and the coding sequences of these gene were analyzed. The result demonstrated that the cloned COR gene sequence was highly homologous to the other COR gene family members showing 98.96% identity to COR1.1. The cloned BBE gene sequence was 94.84% identified with the released BBE genes in GenBank previously. Based on the cDNA sequences of COR and BBE,two fragments about 400～500 bp from each gene with lower identity among them were cloned. The fusion gene BC(744 bp) is fused by the PCR technique. Then the promoter CaMV 35S driven,containing'forward BC fusion fragments-reverse pdk intron-reverse BC fusion fragments',plant siRNA expression vector were constructed based on the vectors pHANNIBAL and pART27. Inhibition efficiency of the expression vector to the morphine synthesis was studied by transforming papaver nudicarule.The work will lay the foundation for breeding a low morphine and high thebaine poppy.