Recovery of Photosynthetic Systems during Rewetting is Quite Rapid in a Terrestrial Cyanobacterium, Nostoc commune

Abstract

Recovery processes of photosynthetic systems during rewetting were studied in detail in a terrestrial, highly drought-tolerant cyanobacterium, Nostoc commune. With absorption of water, the weight of N. commune colony increased in three phases with half-increase times of about 1 min, 2 h and 9 h. Fluorescence intensities of phycobiliproteins and photosystem (PS) I complexes were recovered almost completely within 1 min, suggesting that their functional forms were restored very quickly. Energy transfer from allophycocyanin to the core-membrane linker peptide (L(CM)) was recovered within 1 min, but not that from L(CM) to PSII. PSI activity and cyclic electron flow around PSI recovered within 2 min, while the PSII activity recovered in two phases after a time lag of about 5 min, with half times of about 20 min and 2 h. Photosynthetic CO(2) fixation was restored almost in parallel with the first recovery phase of the PSII reaction center activity. Although the amount of absorbed water became more than 20 times the initial dry weight of the N. commune colony in the presence of sufficient water, about twice the initial dry weight was enough for recovery and maintenance of the PSII activity.

Ideal Osmotic Spaces for Chlorobionts or Cyanobionts Are Differentially Realized by Lichenized Fungi

“…The cephalodia response to dehydration is similar to that of cyanolichens (Figs. 2 and 3) and terrestrial cyanobacteria (Satoh et al, 2002). The response observed for the green algae-containing compartments of S. sorediiferum was similar to that of previously studied chlorolichens (Kosugi et al, 2009), the aerial green alga T. aurea, and cultured Trebouxia spp.…”

“…We recently reported a common physiological profile in desiccation-tolerant photosynthetic organisms such as N. commune (Satoh et al, 2002;Hirai et al, 2004), some bryophytes (Nabe et al, 2007), and chlorolichens (Kosugi et al, 2009). First, PSII activity is lost following the loss of photosynthesis.…”

“…g Data from a previous report (Kosugi et al, 2010b). h Data from a previous report (Satoh et al, 2002). Data from a previous report (Hirai et al, 2004).…”

“…An increase in compatible solutes prevents water loss or increases water uptake from the air when humidity is high (Lange et al, 1988). It has been observed, however, that the intracellular solute concentration is low (corresponding to a sorbitol concentration of approximately 0.22 M) in the desiccation-tolerant terrestrial cyanobacterium Nostoc commune (Satoh et al, 2002;Hirai et al, 2004). N. commune photosynthetic activity is lost when incubated in low sorbitol concentrations (Hirai et al, 2004), whereas a Trebouxia spp.…”

Responses of photosynthetic activity in the drought-tolerant cyanobacterium, Nostoc flagelliforme to rehydration at different temperature

“…Qian et al (1989) have reported that the recovery of photosynthesis occurs mainly during the rainy season in which the recovered photosynthesis provides compounds and energy for the growth and reproduction of N. flagelliforme. Many studies on the photosynthetic function of Nostoc commune in response to dehydration and rehydration have been performed (Hirai et al, 2004;Satoh et al, 2002), but the rate of photosynthesis recovery in N. flagelliforme was shown to be more rapid than that in N. commune (Scherer et al, 1984). Previous studies showed that the photosynthetic resumption of N. flagelliforme not only depended on light, potassium, and water (Gao et al, 1998b;Huang et al, 2005;Qiu and Gao, 1999), but also required de novo protein synthesis (Qiu et al, 2004).…”