The red alga ‘Bangia’ sp. ESS1, a ‘Bangia’ 2 clade member, responds to heat stress via accelerated asexual reproduction and acquires thermotolerance based on heat-stress memory. However, whether these strategies are specific to ‘Bangia’ 2, especially ‘Bangia’ sp. ESS1, or whether they are employed by all ‘Bangia’ species is currently unknown. Here, we examined the heat-stress responses of ‘Bangia’ sp. ESS2, a newly identified ‘Bangia’ clade 3 member, and Bangia atropurpurea. Intrinsic thermotolerance differed among species: Whereas ‘Bangia’ sp. ESS1 survived at 30 °C for 7 days, ‘Bangia’ sp. ESS2 and B. atropurpurea did not, with B. atropurpurea showing the highest heat sensitivity. Under sublethal heat stress, the release of asexual spores was highly repressed in ‘Bangia’ sp. ESS2 and completely repressed in B. atropurpurea, whereas it was enhanced in ‘Bangia’ sp. ESS1. ‘Bangia’ sp. ESS2 failed to acquire heat-stress tolerance under sublethal heat-stress conditions, whereas the acquisition of heat tolerance by priming with sublethal high temperatures was observed in both B. atropurpurea and ‘Bangia’ sp. ESS1. Finally, unlike ‘Bangia’ sp. ESS1, neither ‘Bangia’ sp. ESS2 nor B. atropurpurea acquired heat-stress memory. These findings provide insights into the diverse heat-stress response strategies among species from different clades of ‘Bangia’.
Bibliographical noteAcknowledgments: We are grateful to Hiromi Nakao from Betsukai Fishery Cooperative, Shyoichi Itakura from the Hiyama Fisheries Extension Office, Yoshitomo Hamaya from the Esashi Branch of the Fisheries Co-operative Association of Hiyama, and Hidehiko Sasaki from the Main Branch of the
Fisheries Co-operative Association of Hiyama for permission and support in collecting seaweed on Kamomejima Island in Esasi. We also thank Ryunosuke Irie for technical assistance in phylogenetic analysis, Chengze Li for the maintenance of ‘Bangia’ sp. ESS2, and Yuji Hiwatashi for technical assistance in microscopic observation. Ho Viet Khoa was supported by Ministry of Education, Culture, Sports, Science and Technology of Japan. Puja Kumari is an International Research Fellow supported by JSPS with Postdoctoral Fellowship for Research in Japan (Standard). We also thank Hiroyuki Mizuta for permission of Ho Viet Khoa to study in the Miyagi University
- Bangia atropurpurea
- ‘Bangia’ sp
- heat stress
- asexual reproduction
- stress memory
- ‘Bangia’ sp.