Cyanobacterial sucrose metabolism and the synthesis of sucroglucans after a salt treatment

G. CALÓ; W.A. VARGAS; H.G. PONTIS; G.L. SALERNO

Villa Carlos Paz, Córdoba, Argentina

Congreso; XLIV Reunión Anual de la SAIB (Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

<!-- /* Font Definitions */ @font-face {font-family:Times; panose-1:2 2 6 3 5 4 5 2 3 4; mso-font-alt:"Times New Roman"; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:536902279 -2147483648 8 0 511 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Times; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-ansi-language:ES-AR; mso-fareast-language:ES;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} /* List Definitions */ @list l0 {mso-list-id:1874154398; mso-list-type:simple; mso-list-template-ids:1312605318;} @list l0:level1 {mso-level-text:"[%1]"; mso-level-tab-stop:18.0pt; mso-level-number-position:left; margin-left:18.0pt; text-indent:-18.0pt; mso-ansi-font-size:12.0pt; font-family:"Times New Roman";} ol {margin-bottom:0cm;} ul {margin-bottom:0cm;} --> Whereas many plant species synthesized sucrose oligosaccharides to cope abiotic stress, some filamentous nitrogen-fixing cyanobacteria  (photosynthetic oxygen evolving prokaryotes), accumulate water soluble polymers with the general names of sucroglucans as a response to environmental stress. The structure of the members was recently elucidated, consisting in a series of non-reducing sucrose derivative, where sucrose is linked through its hemiacetalic hydroxyl to de position 2 of the glucose moiety of sucrose.  We investigated the accumulation of these polymers in Anabaena  (Nostoc) sp. PCC 7120 and in two derivative mutants: one of them has an increase sucrose production, and the other one is sensitive to salt stress. We conclude that salt stress is not cope but the only presence of  a high sucrose content when it is accompanied by an abolishment of sucroglucan accumulation. Our results indicate that sucrose may not be involved in the polymer synthesis.