Widespread occurrence and unexpected diversity of red‐shifted chlorophyll producing cyanobacteria in humid subtropical forest ecosystems

• Published in: Environmental microbiology 2019-04, Vol.21 (4), p.1497-1510
• Main Authors: Zhang, Zhong‐Chun, Li, Zheng‐Ke, Yin, Yan‐Chao, Li, Yaqiong, Jia, Yu, Chen, Min, Qiu, Bao‐Sheng
• Format: Article
• Language: English
• Subjects: Aquatic ecosystems; Aquatic plants; Biodiversity; Carbon Cycle; Carbon fixation; Chlorophyll; Chlorophyll - analogs & derivatives; Chlorophyll - metabolism; Chlorophylls; Cyanobacteria; Cyanobacteria - classification; Cyanobacteria - metabolism; Cyanobacteria - physiology; Ecosystem; Ecosystems; Forest ecosystems; Forests; Freshwater; Genera; Humidity; Inland water environment; Light; Limestone; Marine environment; Niches; Phylogeny; Surveying; Terrestrial ecosystems; Terrestrial environments; Tropical forests; White light
• ISSN: 1462-2912; 1462-2920
• DOI: 10.1111/1462-2920.14582

Summary Discovery of red‐shifted chlorophyll d and f in cyanobacteria has opened up new avenues to estimate global carbon fixation driven by far‐red light. Shaded habitats in humid subtropical forest ecosystems contain an increased proportion of far‐red light components relative to residual white light. After an extensive survey of shaded ecosystems within subtropical forests, wide occurrence of red‐shifted chlorophyll‐producing cyanobacteria was demonstrated by isolated Chl f‐producing and Chl d‐containing cyanobacteria. Chl f‐producing cyanobacteria were classified into the genera of Aphanocapsa and Chroococcidiopsis and two undescribed genera within Leptolyngbyaceae. Newly isolated Chl d‐containing Acaryochloris sp. CCNUM4 showed the closest phylogenetic relationship with Acaryochloris species isolated from marine environments. Acaryochloris sp. CCNUM4 produced Chl d as major photopigment, and Chl f‐producing cyanobacteria use Chl a under white light conditions but Chl a + f under far‐red light conditions. Their habitats are widely distributed in subtropical forest ecosystems and varied from mosses on limestone to macrophyte and freshwater in the streams and ponds. This study presents a significant advance in the knowledge of distribution and diversity of red‐shifted chlorophyll‐producing cyanobacteria in terrestrial ecosystems. The results suggest that Chl f‐producing and Chl d‐containing cyanobacteria might be important primary producers in far‐red light dominant niches worldwide.