The Ability of Locusta Migratoria L. to Perceive Plant Surface Waxes

Author(s):  
E. A. Bernays ◽  
W. M. Blaney ◽  
R. F. Chapman ◽  
A. G. Cook
2009 ◽  
pp. 157-181 ◽  
Author(s):  
Sanford D. Eigenbrode ◽  
William E. Snyder ◽  
Garrett Clevenger ◽  
Hongjian Ding ◽  
Stanislav N. Gorb

2002 ◽  
Vol 42 (6) ◽  
pp. 1091-1099 ◽  
Author(s):  
S. D. Eigenbrode

1971 ◽  
Vol 27 (1) ◽  
pp. 13-14 ◽  
Author(s):  
J. E. Allebone ◽  
R. J. Hamilton ◽  
T. A. Bryce ◽  
W. Kelly
Keyword(s):  

1998 ◽  
Vol 180 (19) ◽  
pp. 5144-5150 ◽  
Author(s):  
Yeon-Ki Kim ◽  
Daoxin Li ◽  
Pappachan E. Kolattukudy

ABSTRACT Hard-surface contact primes the conidia of Colletotrichum gloeosporioides to respond to plant surface waxes and a fruit-ripening hormone, ethylene, to germinate and form the appressoria required for infection of the host. Our efforts to elucidate the molecular events in the early phase of the hard-surface contact found that EGTA (5 mM) and U73122 (16 nM), an inhibitor of phospholipase C, inhibited (50%) germination and appressorium formation. Measurements of calmodulin (CaM) transcripts with a CaM cDNA we cloned from C. gloeosporioides showed that CaM was induced by hard-surface contact maximally at 2 h and then declined; ethephon enhanced this induction. The CaM antagonist, compound 48/80, completely inhibited conidial germination and appressorium formation at a concentration of 3 μM, implying that CaM is involved in this process. A putative CaM kinase (CaMK) cDNA of C. gloeosporioides was cloned with transcripts from hard-surface-treated conidia. A selective inhibitor of CaMK, KN93 (20 μM), inhibited (50%) germination and appressorium formation, blocked melanization, and caused the formation of abnormal appressoria. Scytalone, an intermediate in melanin synthesis, reversed the inhibition of melanization but did not restore appressorium formation. The phosphorylation of 18- and 43-kDa proteins induced by hard-surface contact and ethephon was inhibited by the treatment with KN93. These results strongly suggest that hard-surface contact induces Ca2+-calmodulin signaling that primes the conidia to respond to host signals by germination and differentiation into appressoria.


1999 ◽  
Vol 181 (11) ◽  
pp. 3571-3577 ◽  
Author(s):  
Zhi-Mei Liu ◽  
Pappachan E. Kolattukudy

ABSTRACT Fungal conidia contain chemicals that inhibit germination and appressorium formation until they are well dispersed in a favorable environment. Recently, such self-inhibitors were found to be present on the conidia of Magnaporthe grisea, and plant surface waxes were found to relieve this self-inhibition. To determine whether the self-inhibitors suppress the expression of early genes involved in the germination and differentiation of conidia, the calmodulin gene was chosen as a representative early gene, because it was found to be expressed early in Colletotrichum gloeosporioides andColletotrichum trifolii differentiation. After calmodulin cDNA and genomic DNA from M. grisea were cloned, the promoter of the calmodulin gene was fused to a reporter gene, that for green fluorescent protein (GFP), and transformed into the M. grisea genome. Confocal microscopic examination and quantitation of expression of GFP green fluorescence showed (i) that the expression of the calmodulin gene decreased significantly when self-inhibition ofM. grisea appressorium formation occurred because of high conidial density or addition of exogenous self-inhibitors and (ii) that the expression level of this gene was restored when self-inhibition was relieved by the addition of plant surface waxes. The increase in fluorescence correlated with the percentage of conidia that formed appressoria. The induction of calmodulin was also confirmed by RNA blotting. Concanavalin A inhibited surface attachment of conidia, GFP expression, and appressorium formation without affecting germination. The high correlation between GFP expression and appressorium formation strongly suggests that calmodulin gene expression and appressorium formation require surface attachment.


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