The Differential Expression Of MADS-box Transcription Factor In Banana Roots Under Fusarium Oxysporum F.Sp. Cubense And Abiotic Stress

The banana is known as the tropical and sub-tropical fruit and is recognized as the fourth most important crop of the developing countries. Banana is very sensitive to climatic conditions and soil. The moisture, temperature and salinity are the main limiting factors of the banana plantation, which restrict the high yield and quality of banana. Moreover, banana industry is threatened by pathogenic bacteria especially the banana Fusarium oxysporum f. sp. Cubense in recent years, The key step to solve the problem is to isolate the defense-related functional genes and make full use of them. Exploring stress tolerance-related genes has become a hot spot in banana genetic improvement.MADS-box genes are an important class of transcription factors, the function is diverse. Studies show that it mainly involved in flowers, fruit, root development. A few reported that MADS-box genes related to abiotic stress tolerance, can be regulated by salt damage, low temperature and drought stress, and in the banana wilt disease, or the role has not been reported, this study hopes to explore on MADS-box genes in the banana wilt disease.Thirteen MADS-box gene fragments named MuMADS3-MuMADSl5 were isolated based on the obtaining of banana root transcriptome under Fusarium oxysporum f. sp. Cubense tropical race 4 (Foe 4) infection. Eight of them were full-length genes and the other were fragments. The result of sequence analysis showed that the deduced amino acid sequences of these genes contained highly conserved MADS-box domain and belonged to typical MIKC-type MADS-box proteins. QRT-PCR analysis showed that most of the genes were highly expressed in the roots, few of them were also highly expressed in other organs. It was speculated that MuMADS3-MuMADS15 played different roles in flower development, fruit mature, pollen development and stress resistance.In order to study the relationship between MuMADS3-MuMADS15 and Fusarium wilt, QRT-PCR was used to research the differential expression of MuMADS3-MuMADS15 gene in banana plants ’Cavendish’(susceptible wild-type) and ’Nongke No1’(resistant mutant) infected by Foe 4. Results showed that expressions of 13 genes changed with infection time. MuMADS3, MuMADS7, MuMADS8 in susceptible and resistant varieties under Foe 4 showed significantly different expression patterns, probably in banana roots and Foe 4 interaction plays an important role.In order to study the response of MuMADS3-MuMADS15 to abiotic stresses, banana seedlings have been treated with NaCl, low-temperature and drought. RT-PCR analysis showed that some MADS-box genes strongly induced by salt stress, low-temperature and drought, suggesting that some MADS-box genes might be involved in the response process of banana under salt stress, low-temperature and drought stress.