Evaluation of disease resistance and tolerance to elevated temperature stress of the selected tissue-cultured Kappaphycus alvarezii Doty 1985 under optimized laboratory conditions

Abstract

Information on the abiotic stress tolerance and ice-ice disease resistance properties of tissue-cultured is scarce and can pose a big hurdle to a wider use of tissue-cultured seaweed in the industry. Here, we reported on a study of seaweed-associated bacteria diversity in farmed and tissue-cultured, and ice-ice disease resistance and elevated growth temperature tolerance of tissue-cultured in laboratory conditions. A total of 40 endophytic seaweed-associated bacteria strains were isolated from 4 types of samples based on their colony morphologies, Gram staining properties and 16S rRNA gene sequences. Bacteria strains isolated were found to belong to sp., sp., sp., sp., sp., sp., sp., sp., sp., sp. and sp. strain ABI-TU15 isolated in this study showed agar-degrading property when analyzed using agar depression assay. Disease resistance assay was performed by infecting healthy with 10 cells/mL sp. ABI-TU15. Severe ice-ice disease symptoms were detected in farmed seaweeds compared to the tissue-cultured. Besides disease resistance, tissue-cultured showed better tolerance to the elevated growth temperatures of 30 and 35 °C. In conclusion, our overall data suggests that tissue-cultured exhibited better growth performance than farmed seaweeds when exposed to elevated growth temperature and ice-ice disease-causing agent.

Ice‐Ice disease: An environmentally and microbiologically driven syndrome in tropical seaweed aquaculture

“…Searches of both sequences against the NCBI GenBank database reveal that the sequence of Aris (2011) 35 is not identical to any characterized species, instead showing equal sequence identity (98.4%) to characterized Vibrio species V. alginolyticus, V. diabolicus, V. neonatus, V. orientalis and V. parahaemolyticus. The much shorter (130 bp compared with 1300 bp) sequence of Azizi et al 37 is 100% identical to V. alginolyticus and V. diazotrophicus (a non-pathogenic, nitrogen-fixing species).…”

“…The bacterial genera Vibrio and Pseudomonas, identified using biochemical tests, are frequently isolated from IID-affected eucheumatoid tissues ( 2). In many studies, almost all bacteria isolated from IID-affected tissue are Gram negative, though Azizi et al 37 acknowledge that this may potentially be the result of bias in the culturing conditions used. Largo et al 76 report differences in the counts and diversity of colonies obtained using growth media, further suggesting that cultivation conditions influence bacteriological studies.…”

“…In contrast, IID depigmentation is most commonly observed at the base of the thallus but may also spread to apical regions (Figure 2a, b). 21,35,36 This depigmentation is often followed by the softening of affected thalli, and the eventual disintegration of diseased tissue 34,37,38 (Figure 2c). Progression of IID is varied (Table 1), with no definitive studies to date attempting to document disease progression systematically in individual specimens.…”

“…Largo et al 76 report differences in the counts and diversity of colonies obtained using growth media, further suggesting that cultivation conditions influence bacteriological studies. 35,37,76 These sequences show low identity (92%) to each other, and thus do not represent the same species or strain. Each lineage was able to induce IID in inoculated healthy tissue, which may suggest that IID-associated Vibrio spp.…”

Ice-Ice Disease in Commercially Cultivated Seaweeds Kappaphycus spp. and Eucheuma spp.: A Review on the Causes, Occurrence, and Control Measures

“…Tissue-cultured K. alvarezii produced from the laboratory is also unsusceptible to ice-ice disease and better resistant towards extreme temperatures of 30 and 35 °C than farmed seaweeds (Azizi et al, 2018). Also, E.…”