Over-expression of Chinese cabbage calreticulin 1, BrCRT1, enhances shoot and root regeneration, but retards plant growth in transgenic tobacco.
Calreticulin (CRT) is a ubiquitously expressed, high capacity Ca(2+)-binding protein that is involved in intracellular Ca(2+) homeostasis and molecular chaperoning in the endoplasmic reticulum (ER). A cDNA encoding a calreticulin, BrCRT1 (Brassica rapa Calreticulin 1), has been isolated from Chinese cabbage (B. rapa subsp. pekinensis) flower bud. Constitutive over-expression of the BrCRT1 gene promotes robust shoot production and root formation at sub-optimal concentrations of BA/NAA, which are important factors controlling plant regeneration in tissue culture. In contrast, the suppressed BrCRT1 line exhibited a slight reduction of shoot and root regeneration. In spite of enhanced regeneration in tissue culture, the seedling and plant growth rate was inhibited in soil. The steady state level of BrCRT1 transcripts was sensitive to exogenous auxins and cytokinins, and rapidly accumulated within 30 min, and this induction required de novo protein synthesis. Together with the results of transgenic tobacco plants and mRNA analysis in Chinese cabbage, our data suggest that BrCRT1 genes may up-regulate the competency of vegetative tissue to respond to hormonal signals involved in shoot and root regeneration processes.
Jin
Zheng-Lu
ZL
Division of Applied Life Science (BK21), Environmental Biotechnology Research Center and PMBBRC, Gyeongsang National University, 660-701 Jinju, Korea.
Hong
Joon Ki
JK
Yang
Kyung Ae
KA
Koo
Ja Choon
JC
Choi
Young Ju
YJ
Chung
Woo Sik
WS
Yun
Dae-Jin
DJ
Lee
Sang Yeol
SY
Cho
Moo Je
MJ
Lim
Chae Oh
CO
D001483:Base Sequence; D001593:Benzyl Compounds; D029741:Brassica rapa / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D037282:Calreticulin / Q000235:genetics*; D004274:DNA, Recombinant / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects; D017343:Genes, Plant; D007701:Kinetin / Q000494:pharmacology; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000502:physiology; D018520:Plant Shoots / Q000502:physiology; D030821:Plants, Genetically Modified; D011687:Purines; D012038:Regeneration; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism
D001593:Benzyl Compounds; D037282:Calreticulin; D004274:DNA, Recombinant; D009280:Naphthaleneacetic Acids; D010937:Plant Growth Regulators; D011687:Purines; C034182:1-naphthaleneacetic acid; C480551:benzylaminopurine; D007701:Kinetin