EKSPRESI LYSR FAMILY GENE REGULATOR PADA Pectobacterium brasiliense DENGAN PERLAKUAN MADU MANUKA

Lia Erlika, Tri Joko, S.P., M.Sc., Ph.D; Dr. Adyatma Irawan Santosa, S.P., M.Sc

2024 | Tesis | S2 Fitopatologi

LysR-type transcriptional regulator (LTTR) merupakan regulator transkripsi terbesar pada prokariot. Ekspresi gen virulensi dan gen universal stress protein (usp) pada Pectobacterium brasiliense dilaporkan menurun setelah terpapar madu manuka. Madu manuka juga diketahui menghambat pertumbuhan P. brasiliense, namun pengaruhnya terhadap LysR family gene regulator dari patogen busuk lunak ini belum diteliti. Penelitian ini bertujuan untuk mengetahui kisaran inang P. brasiliense, sekuens dan kekerabatan LTTR pada P. brasiliense dan ortolognya dari Enterobacteriales dengan menggunakan analisis filogenetik serta multiple sequence alignment (MSA). Efek madu manuka terhadap ekspresi LTTR diamati menggunakan PCR semi-kuantitatif dan quantitative real time polymerase chain reaction (qRT-PCR). Hasil penelitian menunjukkan isolat P. brasiliense yang dinokulasikan menimbulkan gejala pada tanaman tomat, terong, cabai, tembakau, sawi sendok, kubis bunga, kaktus, seledri dan bawang merah, namun tidak memicu gejala pada padi, jagung, dan pisang. Gen regulator IlvY, KS44_01725, KS44_07475 pada P. brasiliense memiliki kekerabatan paling dekat dengan P. polaris, BenM berkerabat dekat dengan P. versatile, sedangkan gen regulator HdfR dan LrhA berkerabat paling dekat dengan P. carotovorum. Analisis ekspresi LTTR yaitu benM, ilvY, KS44_01725, dan KS44_07475 dari P. brasiliense menunjukkan penurunan ekspresi 39%, 50%,  85%, dan 97% secara berurutan, sedangkan lrhA dan hdfR menunjukkan peningkatan ekspresi sebesar 26?n 4% dalam perlakuan madu manuka 5% (w/v).  

The LysR-type transcriptional regulator (LTTR) is the largest transcription regulator in prokaryotes. The expression of virulence genes and universal stress protein (usp) genes in Pectobacterium brasiliense was reported to decrease after exposure to manuka honey. Manuka honey is also known to inhibit the growth of P. brasiliense, but its effect on the LysR family gene regulator of this soft rot pathogen has not been studied. This study aims to determine the host range of P. brasiliense, the sequence and relationship of the LTTR in P. brasiliense and its orthologs from Enterobacteriales using phylogenetic analysis and multiple sequence alignment (MSA). The effect of manuka honey on the expression of the LTTR was observed using semi-quantitative PCR and quantitative real time polymerase chain reaction (qRT-PCR). The results showed that the inoculated P. brasiliense isolates induced symptoms on tomato, eggplant, chili, tobacco, bok choy, cauliflower, cactus, celery and shallots, but did not induce symptoms on rice, corn, and bananas. IlvY, KS44_01725, KS44_07475 genes regulator of P. brasiliense are most closely related to P. polaris, BenM is closely related to P. versatile, while HdfR and LrhA gene regulator are most closely related to P. carotovorum. Expression analysis of the LTTRs, namely benM, ilvY, KS44_01725, and KS44_07475 from P. brasiliense, showed a decrease in expression of 39%, 50%, 85%, and 97% respectively. Meanwhile, lrhA and hdfR showed an increase in expression of 26% and 4% respectively in the 5% (w/v) manuka honey treatment. 

Kata Kunci : LTTR, madu manuka, Pectobacterium brasiliense, q-PCR