gibberellin (ga) regulates strigolactone (sl) biosynthesis · hyphal branching in arbuscular...
TRANSCRIPT
Gibberellin (GA) regulates strigolactone (SL) biosynthesis
S. Ito, M. Umehara, A. Hanada, S. Yoshida, J. Kyozuka, M. Ueguchi-Tanaka, M. Matsuoka, K. Shirasu, S. Yamaguchi, T. Asami
Hyphal branching in arbuscular
mycorrhizal fungi
Akiyama et al., Nature
Shoot branching
Umehara et al., Nature
Root parasitic weed germination
Cook et al., Science SL deficient
mutant
Wild-type
Mock SL treatment
Structure of SL (2’-epi-5-deoxystrigol: epi-5DS)
Mock SL treatment
P
Carotenoid
SLs
AuxinAbscisic acid
Phosphate
López-Ráez et al., 2010
Yoneyama et al., 2007
Ferguson et al., 2007
Many chemicals control SL biosynthesis
Cytokinin
0 µM 1 µM
One of the strigolactone biosynthesis inhibitors (TIS102)
TIS102 concentration
GA3 reduces the epi-5DS level in rice root exudates
GA3
N.D.
N.D. : Not detected
GA3
・ seed germination・ stem elongation・ flowering・ fruit ripening
・ branching
0 0.1 1 100105000
BL GR24
Root exudates
Roots
0 0.1 1 100105000
BLGR24
GA3 concentration (nM)
GA3 concentration (nM)
GA3 reduces the SL levels in rice
control
GA3
2’-epi-orobanchol Epi-5DS
GA3 GA1 GA4 GA8 GA34
Root exudate
Roots
GA3 GA1 GA4 GA8
Active GAs reduce the SL levels
GA1 GA8
GA3 GA4
Structure of gibberellins
Root exudate
Roots
osga3ox2WT
osga3ox2
GA3 also reduces the SL levels in GA biosynthesis mutant
GA3 concentration (nM)
WT GA defficient mutant
gid2-2
gid2-2
Roots
Root exudate
GA3 concentration (nM)
GA3 concentration (nM)
WT
WT
GA3 doesn’t reduce the SL levels in GA signaling mutant
5 cm
WT gid2-2
Root exudate
WT slr1
GA3 concentration (nM)
5 cm
WT slr1
SL is not detceted in constitutive GA response mutant
GA reduce the SL levels depending on GA signaling.
Roots
Root exudate
0 0 50
d3 mutantWT
GA3 concentration (nM)
GA3 also reduces the SL levels in SL signaling mutant
GA reduce the SL levels independent of SL signaling.
WT d3
GA3 concentration (nM)
D17
GA reduces the transcript levels of SL biosynthesis genes
Strigolactones
carotenoid
D17 (CCD7)
D10 (CCD8)
D27
DW GR24 control GA3 GA3
+GR24
Root exudate
GA reduces the Striga germination stimulants in rice root exudates
GR24 1 µM, GA3 10 nM
GA-treated rice reduces the Striga infection
＊: P<0.05
＊＊
＊
Conclusion
GA reduces the SL levels.the transcript levels of SL biosynthesis genes.the Striga infection.
Controlling the GA biosynthesis or signaling pathway in plants might become one of the way
to contol the root parasitic weed infection.