| Rice suspension cell and callus were treated with fungal elicitor-xylanase or the extract from Magnaporthe grisea.We found:(1) Xylanase treatment induced rapid accumulation of H2O2 and O2- in rice suspension cells.Xylanase also induced the expression of defense genes.The expression of chitinase was induced obviously in suspension cells after 1h treatment while the expression of PR10 was induced after 12h treatment.Xylanase treatment induced 80%cell death in 24h.Xylanase induced the synthesis of sakuranetin in callus after 24h to 72h treatment.Then callus turned brown,decreased in fresh weight and declined the density of callus when treated with xylanase in 20d.(2) EFM treatment induced the expression of PR10 and chitinase,the production of sakuranetin,and calli turned brown,decreased in fresh weight and declined the density of callus.The preliminary results showed that suspension cell and callus are convenient and suitable plant materials for studying the mechanisms of the resistance to Magnaporthe grisea in rice.Both xylanase and EFM induced rice resistance response.Phospholipase D(PLD) and phosphatidic acid(PA) are essential signal molecules in the plant responses to various biotic and abiotic cues.Using suspension cell and callus,we study the mechanism of rice blast resistance and the PLD effects.We found:(1) Xylanase elicitor and EFM activates PLDα,but not increase the content of PLDαand the expression of plda gene.(2) In the presence of 1-butanol,the second phase generation of H2O2 was no longer detected;the sakuranetin production and cell death was clearly suppressed.(3) Exogenously applied PA itself induced the second phase generation of H2O2,the sakuranetin production and cell death.(4) H2O2 was involved in cell death induced by xylanase.Scavenging of H2O2 suppressed the cell death induced by xylanase or PA.The preliminary results showed that Phospholipase D and phosphatidic acid are involved in the responses of rice cells to xylanase elicitor or EFM.
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