| Meloidogyne graminicola Golden and Birchfield,1965(Mg)is one of the most serious plant parasitic nematodes in rice production,which can cause rice yield reduction.The occurrence area of M.graminicola in major rice growing areas in China is expanding year by year,which has become an important factor seriously affecting the safe production of rice.In this study,rice root-knot nematodes were investigated and identified as M.graminicola.On this basis,the infection law,flooding control measures and transcriptome of rice infected by M.graminicola for 7 days were preliminarily studied.The main results are as follows:1.The pathogen of rice root-knot nematode disease in Anqing and Wuhu,Anhui Province was identified by morphology and molecular biology.It was found that the de-Man morphological characteristics of female,male and second-stage juveniles were basically consistent with the reported M.graminicola.Mg-F3/R2 specific primer combination was used to verify that 369 bp fragments were amplified,and the homology of r NDA ITS、18S、28S and mt DNA COI sequences with the related genes of M.graminicola in Gen Bank was more than 99%.Therefore,it is confirmed that the pathogen of the disease is M.graminicola.2.By using Pluronic F-127 colloid and acid fuchsin staining to study its infection and development law,it was found that under the laboratory condition of 25 ℃,the second-stage juveniles began to gather to the rice root tip after co culture for 2 hours,the second-stage juveniles began to invade the interior of the root tip after 12 hours,the rice root tip began to expand and show small root nodules after 24 hours,and the root nodules began to show a typical "hook" shape,the third-stage juveniles appeared after 7 days,and the eggs appeared after 14 days,The second-stage juveniles began to appear on the 21 st day,indicating that it took only 21 days for M.graminicola to complete a life cycle under the condition of 25 ℃.3.Effects of flooding treatment on the survival of soil nematodes and second-stage juveniles of M.graminicola were studied.The results showed that the decline rate of the second-stage juveniles of M.graminicola in 0 ～ 20 cm soil was over 95.2% after 7 days of flooding treatment,and the decrease of dissolved oxygen concentration in soil was an important cause of the death of M.graminicola.The second-stage juveniles of M.graminicola were mainly concentrated in 0 ～ 15 cm soil in naturally occurring paddy fields,so it was speculated that flooding treatment was one of the important agricultural control measures to control rice root-knot nematodes caused by M.graminicola.4.By analyzing the transcriptome data of rice infected by M.graminicola for 7 days,it was found that there were 1140 significantly up-regulated genes and 1176 significantly down regulated genes in rice,481 significantly up-regulated genes and 1191 down regulated genes in M.graminicola.At the same time,the RT-q PCR results of 16 rice genes and 12 nematode genes with obvious differential expression were basically consistent with them.It is proved that in the infection stage of M.graminicola infecting rice,the signal transduction,glucose metabolism and disease resistance of rice will change.At the same time,the hormone signal,inflammatory regulation and salivary secretion of M.graminicola will change with the disease resistance response of rice.It provides a reference for further study on the defense mechanism of rice and M.graminicola. |
