Characterization of Two Photosynthetic Mutants of Maize1

Abstract

We describe here the biochemical characteristics of the hcf44 and hcf47 (high chlorophyll fluorescence) mutants of maize (Zea mays L.). Both mutants were sensitive to high light intensities, exhibiting reduced growth and fluorescence intensity. Electron transport through the mutants' photosystem (PS) I and PSII reaction centers was reduced and NADP ؉ photoreduction was absent. Western analysis revealed that the hcf44 mutant was missing some or all of the PsaC, PsaD, and PsaE polypeptides of the PSI reaction center, and reverse transcriptase-polymerase chain reaction demonstrated that this loss was the result of a posttranscriptional event. The hcf47 mutant had reduced levels of many PSI and PSII polypeptides. These data indicate a possible defect in the synthesis or assembly of the PsaC subunit in the hcf44 mutant, whereas the hcf47 mutant may have a more general defect in the biogenesis of photosynthetic membranes. Our results demonstrate the coordinated assembly of the peripheral proteins into the PSI complexes of higher plants and demonstrate the in vivo requirement of PsaC, PsaD, and PsaE subunits for the function of PSI in higher plants.

Small changes in the activity of chloroplastic NADP+‐dependent ferredoxin oxidoreductase lead to impaired plant growth and restrict photosynthetic activity of transgenic tobacco plants

“…To date, comparative investigations with genotypes differing in electron transport components have been carried out mainly with photosynthetic mutants (De Lamotte‐Guery et al ., 1991; Heck et al ., 1999). To our knowledge, transgenic plants with modified properties of the electron transport chain have been described only for the cytochrome b 6 / f complex (Rieske FeS protein).…”

Gene Loci in Maize Influencing Susceptibility to Chilling Dependent Photoinhibition of Photosynthesis

“…These are induced by light and are important to the stability of the thylakoid membrane, the primary site of photoinhibition (Long et al 1994). The hcf loci are generally associated with a wide range of lesions impairing normal development and arrangement of the photosystems and associated antennae on the thylakoid membranes (Heck et al 1999;Felder et al 2001). As yet no function has been ascribed to hcf46 and hcf19 (http//:www.maizegdb.org).…”

Characterization of the ZmDBP4 gene encoding a CRT/DRE-binding protein responsive to drought and cold stress in maize

“…The real-time quantitative RT-PCR (Q-RT-PCR) were conducted using the ABI Prism 7000 system (Applied Biosystems, USA) according to the modified protocol (Livak and Schmittgen 2001). The actin gene, expressed constitutively in maize (Heck et al 1999), was used as an internal reference. The transcript analysis of the ZmDBP4 gene was performed using gene-specific primers (5 0 -G CTACTGAGCTGTAGAGTCTGTC-3 0 and 5 0 -GTGCCA GTGCCAGTACAG-3 0 ), which were located in the 3 0 -terminal region of the gene.…”