Tinangaja and Bristle Top, Coconut Diseases of Uncertain Etiology in Guam, and Their Relationship to Cadang-Cadang Disease of Coconut in the Philippines

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Abstract
The symptomatologies of tinangaja and bristle top, 2 disorders afflicting coconut palms on the island of Guam, were compared with cadang-cadang disease in the Philippines. Nucleic acids were extracted from leaf samples from healthy and diseased palms through a procedure involving precipitation with polyethylene glycol, phenol and chloroform extractions, fractionation with 2 M LiCl, and further purification with cetyltrimethylammonium bromide. Comparative electrophoretic analysis established that 2 low-MW RNA with the same apparent mobilities in 5% polyacrylamide gels as the diagnostic viroid-like RNA (ccRNA-1 and ccRNA-2) associated with cadang-cadang disease were correlated uniquely with tinangaja symptoms. A 3H-labeled DNA probe complementary to ccRNA-1 (cDNA) showed that the tinangaja-related RNA have nucleotide sequences equivalent to ccRNA-1. Tinangaja apparently has the same etiology as cadang-cadang, a disease formerly believed to be restricted to the Philippines. Nucleic acids extracted from coconuts affected with bristle top did not contain such viroid-like RNA.