Text
Bioprospecting of Bacillus pumilus as Biocontrol Against Fungal Plant Pathogens and Plant Growth Promoting through Indole Acetic Acid (IAA) Assay
ABSTRACT
Ade Fajrian 24020114130082 Bioprospecting of Bacillus pumilus as Biocontrol
Against Fungal Plant Pathogens and Plant Growth Promoting through Indole
Acetic Acid (IAA) Assay, under supervise of Anto Budiharjo and Rejeki Siti Ferniah.
The genus Bacillus is one of the well known group of bacteria as Plant GrowthPromoting Rhizobacteria (PGPR) that can support plant growth or otherwise control
the plant pathogens. In this study, three strain of B. pumilus from BIOTEC culture
collection (BCC 7507, TBRC 2887 and TBRC 2903) were investigated for their
potential to be used as fungal pathogen control. The growth characteristics of these B.
pumilus strains were determined by making the growth curve of each strain. Further,
antagonistic activity of B. pumilus against the anthracnose pathogens C. capsici, C.
gloeosporioides and C. acutatum, the rice dirty panicle pathogen Curvularia lunata,
the leaf spot pathogen Alternaria brassicicola, and the rice blast pathogen
Magnoporthe grisea were evaluated by identified the inhibition zone from their
activity. Then, the secondary metabolites produced by these Bacillus strains were also
examined using anti-fungal activity assays. Finally, the amount of Indole Acetic Acid
(IAA) produced by these Bacillus strain were examined by adding 2 mg/ml Ltryptophan into media and measured the OD at wavelength 530 nm. All B. pumilus
strains showed very low biocontrol activity against M. grisea, but not against C.
acutatum, C. Capsici, C. gloeosporioides, A. brassicicola and C. lunata. Culture
extracts derived from these strains did not show any activity against M. grisea in the
spore germination inhibition assay. To determine their ability to promote plant growth,
IAA assay was performed. Results showed that the three B. pumilus strains produced
low levels of IAA compared to positive control P. putida. Together, these results
showed that the three B. pumilus strains did not exhibit strong potential for application
as biocontrol agent.
Keywords: Indole Acetic Acid, secondary metabolites, Antifungal
ABSTRAK
Ade Fajrian, 24020114130082 Bioprospecting Bacillus pumilus sebagai Agen
Biokontrol Terhadap Patogen Tanaman dan Plant Growth Promoting (PGP)
melalui Uji Asam Indol Asetat (IAA), dibawah bimbingan Anto Budiharjo dan
Rejeki Siti Ferniah
Genus Bacillus merupakan salah satu genus yang terkenal sebagai plant growth
promoting Rhizobacteria (PGPR) yang mampu mendukung pertumbuhan tanaman atau
di sisi lain mengontrol pertumbuhan patogen yang merusak tanaman. Berdasarkan
penelitian ini, tiga strain Bacillus pumilus dari BIOTEC culture collection (BCC7507,
TBRC2887 dan TBRC2903) telah diuji untuk melihat potensinya sebagai biokontrol
patogen tanaman. Kurva pertumbuhan strain B. pumilus dibuat untuk mengidentifikasi
karakteristik pertumbuhan dari masing-masing strain. Selanjutnya dilakukan uji
atagonis, dengan menumbuhkan B. pumilus di dalam kultur petri enam jenis pathogen
yaitu Colletotricum acutatum, C. capsici, C. gloeosporioides yang merupakan
pathogen atrachnose, Curvularia lunata yang merupakan bakteri penyebab penyakit
gabah kotor pada padi, Alternaria brassicicola yang menyebabkan bercak hitam pada
daun dan Maghnoporte grisea yaitu patogen penyebab busuk leher pada batang padi.
Metabolit sekunder yang dihasilkan oleh bakteri B. pumilus juga diujikan terhadap
patogen tanaman tersebut dengan menggunakan uji aktivitas anti-fungal. Terakhir,
kemampuan B. pumilus untuk menghasilkan asam indol asetat (IAA) juga dihitung
dengan menumbuhkan bakteri di media yang diperkaya dengan tambahan 2 mg/ml Ltriptofan dan konsentrasi IAA yang dihasilkan dihitung pada OD dengan panjang
gelombang 530 nm. Hasil penelitian menunjukkan aktivitas biokontrol yang rendah
terhadap M. grisea, namun tidak menunjukkan aktivitas terhadap C. acutatum, C.
Capsici, C. gloeosporioides, A. brassicicola dan C. lunata. Ekstraksi kultur B. pumilus
juga menunjukkan hasil negatif dalam uji daya hambat pertumbuhan spora M. grisea.
Uji kandungan IAA yang diproduksi oleh B. pumilus, juga menunjukkan produksi yang
rendah dibandingkan dengan Pseudomonas putida sebagai kontrol positif.
Kata kunci:, asam indol asetat, metabolit sekunder, Antifungal
1273B19I | 1273 B 19-i | Perpustakaan FSM Undip (Referensi) | Tersedia |
Tidak tersedia versi lain