| Sensitivity of 10 experimental F. graminearum isolates against MBC was verified. EC50 values of MBC sensitive isolates (MBCS), ZF43, ZF2032 and No.2021 were 0.5411,0.6288 and 0.5574 ng active ingredient MBC (A.I)/mL respectively, and incapable of growing at the concentration of 1.4 ug A.I/mL. While ZF43-2, one low MBC-resistant (MBCLR) isolate with the EC50 value of 0.8015ug A.I/mL against MBC, can grow at the concentration of 1.4 ug A.I/ mL, but was inhibited completely at the concentration of 10ug A.I/mL. Field middle MBC resistant (MBCMR) isolates, ZF52, ZF2054 and No.2458 were capable of growing rapidly at the concentration of 10 ng A.I/mL, doing slowly at the concentration of 50 ug A.I/mL, and being controlled completely at the concentration of 100 ug A.I/mL. Induced high MBC-resistant (MBCIHR)isolates,ZF43-2-5 and ZF52-7,and field high MBC resistant(MBCHR) isolate, JT04 were capable of growing rapidly at the concentration of 50 ug A.I/mL and being inhibited completely at the concentration of 100 ug A.I/mL, although 4.72ug A.I/mL EC50 value of ZF43-2-5 against MBC was lower than 20.6620 ug A.I /mL EC50 value of ZF52-7 against MBC. The EC50 value of JT04 against MBC was 20.9495ug A.I/mL ,nearly equal to that of ZF52-7. .Competitions of conidia reproduction between MBCMR isolate No.2458 and MBCS isolate No.2021 of F. graminearum in poor nutrient was studied by method of mixed culture. The conclusion showed that: MBCMR isolate reproduced conidia in pattern of parabola equations: Y=1.00 X 104+36.45T2(during the period of inoculation and the reproduction peak) and Y=1.33 X 106-6.65 X 103T+8.59T2(during the period of the reproduction peak and incubation for 473.5h),while MBCS isolate in pattern of linear equation Y=9.98X 106+4.82X 104T(during the period of inoculation and the reproduction peak), and parabola equation Y=2.78 X 107-9.28 X 104T+1.00 X 102T2 (during the period of the reproduction peak and incubation for 473.5h), when only one isolate was cultured. The models of MBCS and MBCMR isolates had been set up as Ns=-2.99X 103+6.45X 102T-1.13T2 and Nr=-1.43 X 105+2.64 X 104T-46.09T2, respectively when they were equally inoculated and co-cultured. The MBCMR isolate in co-culture predated the moment of conidia reproduction peak by 24h earlier than it was in pure culture, while the sensitive isolate shared the same moment of conidia reproduction both in pure culture and co-culture. Meanwhile, mutual antagonism between MBCMR and MBCS isolates of conidiareproduction sum presented through the whole course, and MBC isolate had dominant to MBCMR isolate during 42.5~190h,and then was defeated during 190-474.5 h.Fragments of r-, a-, a2-tubulin and tubule-associated protein gene (map) of two MBCS isolates ZF43 and ZF2032, one MBCLR isolate 43-2 ,one MBCMR isolates ZF52, one MBCHR isolate JT04 and one MBCIHR isolate 52-7 of F. graminearum were amplified, cloned, sequenced and spliced into the whole sequences by ploymerase chain reactions (PCR) using oligo nucleotide primers of five, triple four synthesized to the whole nucleotide sequences of corresponding genes from NRRJL31084, respectively.The result showed that there were 1868 base pairs(bp), including five introns, coding493 amino acids in the whole nucleotide sequence of r-tubulin gene, one member of the tubulin gene family, which 99% homology were identical to that of Y -tubulin of NRRL31084.The predicted amino acid sequence of the F. graminearum K-tubulin gene was 100% identical to that of r-tubulin gene from reference strain, NRRL31084, although the F. graminearum r-tubulin contained 10-site nucleotide difference in comparison the whole nucleotide sequence of the gene above mentioned with that of r-tubulin from its reference strain. Less homology was observed between the r-tubulin deduced amino acid sequence of F. graminearum and those of the Coprinopsis cinerea and Aspergillus nidulans (72% and 61%, respectively).The whole nucleotide sequence suggested that F. graminearum a -tubulin, another member of the tubulin gene family, had 1718 b... |
PDF Full Text Request