An assessment of the capacity for phosphoenolpyruvate carboxykinase to contribute to C4 photosynthesis. (June 2015)

• Record Type: Journal Article
• Authors: Koteyeva, Nuria K.; Voznesenskaya, Elena V.; Edwards, Gerald E.
• Is Part Of: Plant science. Volume 235(2015:Jun.)
• Page Start: 70
• Page End: 80
• Publication Date: 2015-06
• Subjects: BS bundle sheath -- M mesophyll -- NAD-MDH NAD-malate dehydrogenase -- NAD-ME NAD-malic enzyme -- NADP-ME NADP-malic enzyme -- OAA oxaloacetate -- PEPC phosphoenolpyruvate carboxylase -- PEPCK phosphoenolpyruvate carboxykinase -- TCA tricarboxylic acid; C4 grasses -- C4 eudicots -- C4 photosynthesis -- NADP-ME type -- NAD-ME type -- PEPCK type; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2015.03.004
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: Three types of C4 cycles occur in C4 plants via three C4 acid decarboxylases. PEPCK decarboxylase function in C4 was recently alleged in some C4 eudicots. Amounts of decarboxylases can be examined by enzymatic assays and western blots. Analysis of PEPCK supports its function in C4 cycle in Poaceae but not in eudicots. C4 species can be classified based on the predominant decarboxylase utilized. Abstract: Three C4 acid decarboxylases, phosphoenolpyruvate carboxykinase (PEPCK), NADP-malic enzyme (NADP-ME), and NAD-malic enzyme (NAD-ME) were recruited from C3 plants to support C4 photosynthesis. In Poaceae, there are established lineages having PEPCK type species, and some NADP-ME lineages in which PEPCK contributes to C4 . Besides family Poaceae, recently PEPCK has been reported to function in C4 photosynthesis in eudicot species including Cleome gynandra (Cleomaceae), Trianthema portulacastrum and Zaleya pentandra (Aizoaceae). We evaluated PEPCK by enzyme assay and western blots in representatives of Poaceae, Aizoaceae, Cleomaceae, and Chenopodiaceae compared to that in the PEPCK type C4 grass Spartina anglica . Eragrostis nutans was identified as the first NAD-ME type C4 grass having substantial amounts of PEPCK. In the eudicots, including C. gynandra, Cleome angustifolia, T. portulacastrum, Z. pentandra, and nine C4 members of family Chenopodiaceae (which has the most C4 species and diversity in forms among eudicot families), amounts of PEPCK were generally very low (barely detectable up to 4% of that in S. anglica ). Based on these results, C4 species can be classified biochemically according to the dominant decarboxylase recruited for C4 function; and, Poaceae remains the only family in which PEPCK is known to have a significant role in C4 photosynthesis.