Effects Of Iron On The Perfect Stage Of Curvularia Lunata

Maize Curvalaria Leaf Spot is one of the major leaf diseases in maize,which caused by Curvularia lunata.The teleomorph of Curvularia lunata is Cochliobolus lunata.Sexual development is controlled by the mating-type genes（MAT）,through control of intercellular identification and asci and ascospores production.Moreover,metal ions also play an important role during the growth and metabolism of fungi.Therefore,we investigated the effect of metal ions on perfect stage in C.lunata.Futher research investigated the effect of NPS6,Ftr1 and NPS2 on perfect stage in C.lunata.Role of mating-type genes in the sexual and asexual development of C.lunata and effect on pathogenicity were identified through ClMAT knockout.It was of great significance to understand the perfect stage of the C.lunata.The main results were as follows:1.Effect of 4 kind of metal ions on perfect stage in C.lunataPefect stage abduction of C.lunata was performed on different Sach’s mediums,which contained Fe³⁺,Cu²⁺,Zn²⁺and Mn²⁺,respectively.Results showed that Fe³⁺promoted the production of pseudothecium and asci.Zn²⁺promoted the production of asci.Mn²⁺had no significant effect on the production of pseudothecium and asci.Cu²⁺inhibited the production of pseudothecium.The most effective concentration of Fe³⁺to the production of pseudothecium and asci was 250μM,while higher or lower inhibited it.2.Effect of NPS6,Ftr1 and NPS2 on perfect stage in C.lunataKnockout vector of ClNPS2 of C.lunata was constructed to obtain transformantΔClnps2（MAT1-1）.For all experiments,crosses between C.lunata strains CX-3（MAT1-2）and ZD958（MAT1-1）were set up as WT controls.And we crossedΔClnps6、ΔClftr1 andΔClnps2（all MAT1-2）to tester strain ZD958,respectively.The number of pseudothecium and asci was determined.Transformants that lack NPS6 or Ftr1 gene had insignificant effect on the production of pseudothecium and asci.Transformants that lack NPS2 gene caused generation failure of asci and ascospore.Production of asci and ascospore partially recovered when Fe³⁺was supplied.3.Effect of MAT gene on perfect stage of C.lunataSouthern blot test showed that MAT gene was single copy in C.lunata.Knockout vector of ClMAT of C.lunata was constructed to obtainΔClmat1-1 andΔClmat1-2.There were no significant differences in growth rate,conidia production and resistance response between each transformant and corresponding wild strain.But we found thatΔClmat1-2 had lighter colony color and less aerial hyphae and aerial hyphae ofΔClmat1-1 was less than wild strain.Spore germination rate ofΔClmat1-2 was lower,about 72%at most at 5h.ΔClmat1-1 delayed on spore germination time,gradually approaching wild strain as the increase of germination time.Sensitivity detection showed that transformants as well as wild strains were insensitive to hydrogen peroxide,integrity of cell wall and osmolarity stress.Pathogenicity test of transformants were obviously decreased.No pseudothecia and asci was produced during pefect stage abduction with MAT gene absence.