Ganoderma zonatum Is the Causal Agent of Basal Stem Rot in Oil Palm in Colombia.

Sandra Yulieth Castillo,Anuar Morales,Hernán Mauricio Romero,Yuri Adriana Mestizo,Carmenza Montoya,Héctor Camilo Medina,Greicy Andrea Sarria,María Camila Rodríguez,Luis Felipe González,León Franky Zúñiga

doi:10.3390/jof8030230

Abstract

Basal stem rot (BSR), caused by Ganoderma spp., is one of the most important emerging oil palm diseases in Colombia, and is restricted to two oil palm production areas in the country. To identify the causal agent of the disease, basidiocarp of oil palms affected by BSR were used to prepare isolates, and their pathogenicity was then assessed in pre-nursery plants. Four-month-old oil palm seedlings were inoculated with rubber wood (Hevea brasiliensis) blocks colonized with dikaryotic mycelia of Ganoderma. The incidence, severity, and symptoms of the pathogen were assessed. A multiregional analysis (ITS, rpb2, and tef1-α) was carried out to identify the isolates; all isolates were determined to be Ganoderma zonatum. Phylogenetic analyses with the three regions yielded concordant phylogenetic information and supported the distinction of the isolates with high bootstrap support. Seven isolates (CPBsZN-01-29, CPBsZN-02-30, CPBsZN-03-31, CPBsZN-04-34, CPBsZN-05-35, CPBsZN-06-36, and CPBsZN-07-38) were pathogenic in oil palm, with incidences greater than 90% and a maximum severity of 34%, and the highest severity index was found in isolates CPBsZN-03-31, CPBsZN-04-34, and CPBsZN-06-36. The pathogen was recovered from inoculated oil palms in all cases. This study reveals the pathogenic association of Ganoderma zonatum with BSR in Colombia.

Highlights

Oil palm (Elaeis guineensis and interspecific hybrid OxG (Elaeis oleifera X Elaeis guineensis)) is one of the main agro-industries in Colombia, with a planted area of more than559,000 hectares and a palm oil production of 1,528,739 tons, ranking fourth as a producer worldwide [1]
Among the different Ganoderma species associated with oil palm production in Southeast Asia, G. boninense has been identified as the main causal agent of the disease for its high degree of virulence [6]
The oil palms affected in the field by basal stem rot (BSR) presented foliar symptoms, such as bending of the lower leaves, which can break at some point along the rachis forming a raceme, followed by drying and necrosis of the leaves

Summary

Introduction

Oil palm (Elaeis guineensis and interspecific hybrid OxG (Elaeis oleifera X Elaeis guineensis)) is one of the main agro-industries in Colombia, with a planted area of more than559,000 hectares and a palm oil production of 1,528,739 tons, ranking fourth as a producer worldwide [1]. Crop health is one of the main limiting factors, and bud rot and lethal wilt are the most important oil palm diseases. Among the different Ganoderma species associated with oil palm production in Southeast Asia, G. boninense has been identified as the main causal agent of the disease for its high degree of virulence [6]. This hemibiotrophic basidiomycete causes lethal effects in plants by degrading the lignin and cellulose of the cell walls of the stem through the action of ligninolytic enzymes that affect the xylem, and the transport of nutrients and water, thereby affecting biochemical and physiological processes that impair the normal development of the plant [7,8]

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Conclusion