Pengenalpastian bakteria tanah yang mempunyai aktiviti antikulat terhadap patogen kelapa sawit, Ganoderma boninense

Penyakit reput pangkal batang (BSR) yang berpunca daripada kulat fitopatogen Ganoderma boninense merupakan ancaman terbesar kepada tanaman kelapa sawit di Malaysia. BSR menyebabkan pengurangan hasil tandan sawit dan kematian terhadap pokok kelapa sawit terjangkit, seterusnya menyebabkan kerugian yang besar kepada ekonomi negara pengeluar. Penggunaan racun kimia juga telah diaplikasikan bagi menangani BSR, namun begitu, kaedah ini tidak mampu mengatasi serangan kulat ini. Beberapa kajian telah dilakukan untuk mengenal pasti potensi penggunaan agen kawalan biologi seperti mikroorganisma antagonis dalam mengawal penyakit BSR. Kajian ini bertujuan untuk mengenal pasti mikroorganisma pencilan tempatan yang mempunyai kesan antagonistik terhadap G. boninense. Sebanyak 49 kultur bakteria tulen telah dipencilkan dari kawasan sekitar Bangi, Selangor, Malaysia. Tiga pencilan iaitu masing-masing dua strain daripada genus Burkholderia dan satu daripada Streptomyces menunjukkan aktiviti antagonistik yang kuat terhadap miselia dwikarion G. boninense strain PER71 dengan nilai Peratusan Perencatan Pertumbuhan Radius (PIRG) melebihi 70% dalam dua asai antikulat yang berbeza. Analisis jujukan DNA bagi semua pencilan telah menunjukkan spesies bakteria tersebut mempunyai kesamaan yang tinggi dengan jujukan nukleotida 16S rRNA daripada Burkholderia stagnalis, B. cepacia dan Streptomyces gelaticus. Bakteria yang digunakan di dalam kajian ini mempunyai potensi yang tinggi untuk digunakan sebagai agen kawalan biologi dalam menghalang penyebaran G. boninense terutamanya di dalam ladang kelapa sawit di Malaysia

Evaluation and improvement of protocols for Ganoderma boninense protoplast isolation and regeneration

Ganoderma boninense is the causal agent of basal stem rot (BSR) disease of oil palm. The BSR disease reduces oil palm yield by up to 80% of the average oil yield. Attempts to control the disease caused by this fungus in the field showed varying levels of success and cases of infection increased from year to year. Hence, the development of new efficient methods to control the spread of this fungus should be commenced promptly. To ensure a better strategy is created, more thorough research on the method deploy by this fungus to infect the host at the molecular level need to be carried out first. However, the major limitation in endeavoring into the functional analysis of virulence genes related to the pathogenicity of this fungus was hampered by the unavailability of established methods for protoplast isolation with a high regeneration rate to be used in the genetic manipulation analysis. Thus, in this paper, we report an efficient protocol for protoplast isolation and regeneration in G. boninense and successfully used the isolated protoplasts in PEG-mediated transformation analysis. A large quantity of protoplast was obtained using the protocol that utilizes the following parameters: 3 to 4-day-old mycelia, treated with 1% lysing enzyme and 0.02% Driselase, incubated at 30 °C in an osmotic medium containing 0.6 M mannitol at pH 5.8 for 2 h. The highest protoplast yield was in the range of 8.95 × 109 to 3.12 × 1010 cells/mL per 5 g of mycelia used. The regeneration rate ranged from 9.03% to 22.55%, depending on the regeneration media used. By using 5 μg of vector to transform into 1.0 × 107 protoplast/mL, around 3 – 10 mitotically stable putative transformants were successfully obtained and verified via PCR. This protocol will find useful applications in genetic studies to enhance insight into this poorly characterized and understood phytopathogen

Review Update on the Life Cycle, Plant–Microbe Interaction, Genomics, Detection and Control Strategies of the Oil Palm Pathogen Ganoderma boninense

Plant pathogens are key threats to agriculture and global food security, causing various crop diseases that lead to massive economic losses. Palm oil is a commodity export of economic importance in Southeast Asia, especially in Malaysia and Indonesia. However, the sustainability of oil palm plantations and production is threatened by basal stem rot (BSR), a devastating disease predominantly caused by the fungus Ganoderma boninense Pat. In Malaysia, infected trees have been reported in nearly 60% of plantation areas, and economic losses are estimated to reach up to ~USD500 million a year. This review covers the current knowledge of the mechanisms utilized by G. boninense during infection and the methods used in the disease management to reduce BSR, including cultural practices, chemical treatments and antagonistic microorganism manipulations. Newer developments arising from multi-omics technologies such as whole-genome sequencing (WGS) and RNA sequencing (RNA-Seq) are also reviewed. Future directions are proposed to increase the understanding of G. boninense invasion mechanisms against oil palm. It is hoped that this review can contribute towards an improved disease management and a sustainable oil palm production in this region