Absence of the Lhcb1 and Lhcb2 proteins of the light‐harvesting complex of photosystem II – effects on photosynthesis, grana stacking and fitness

Abstract

SummaryWe have constructed Arabidopsis thaliana plants that are virtually devoid of the major light-harvesting complex, LHC II. This was accomplished by introducing the Lhcb2.1 coding region in the antisense orientation into the genome by Agrobacterium-mediated transformation. Lhcb1 and Lhcb2 were absent, while Lhcb3, a protein present in LHC II associated with photosystem (PS) II, was retained. Plants had a pale green appearance and showed reduced chlorophyll content and an elevated chlorophyll a/b ratio. The content of PS II reaction centres was unchanged on a leaf area basis, but there was evidence for increases in the relative levels of other light harvesting proteins, notably CP26, associated with PS II, and Lhca4, associated with PS I. Electron microscopy showed the presence of grana. Photosynthetic rates at saturating irradiance were the same in wild-type and antisense plants, but there was a 10±15% reduction in quantum yield that re¯ected the decrease in light absorption by the leaf. The antisense plants were not able to perform state transitions, and their capacity for non-photochemical quenching was reduced. There was no difference in growth between wild-type and antisense plants under controlled climate conditions, but the antisense plants performed worse compared to the wild type in the ®eld, with decreases in seed production of up to 70%.

Light-harvesting chlorophyll a/b-binding proteins are required for stomatal response to abscisic acid in Arabidopsis

“…Consistently, previous studies showed that down-regulation of the LHCB members reduced plant tolerance to environmental stresses with lowered seed production (Andersson et al , 2001, 2003; Ganeteg et al , 2004; Kovacs et al , 2006) except for the lhcb3 mutant that showed comparable seed production with that of wild-type plants (Damkjaer et al , 2009). The differences observed in the lhcb3 mutants between our present observations and the previously reported data (Damkjaer et al , 2009) may be due to the characteristics of the different lhcb3 mutants: in the lhcb3 mutant used here (SALK_036200 or N536200), the protein levels of the other LHCB members were not affected (Fig.…”

“…ABA signal transduction has been extensively studied, and numerous signalling components have been identified, which include plasma membrane and intracellular ABA receptors (Shen et al , 2006; Fujii et al , 2009; Ma et al , 2009; Pandey et al , 2009; Park et al , 2009; Wu et al , 2009; Cutler et al , 2010; Shang et al , 2010). Previous reports showed that the members of the LHCB family play an important role in plant adaptation to environmental stresses (Andersson et al , 2001, 2003; Ganeteg et al , 2004; Kovacs et al , 2006), as well as their expression being regulated by ABA (Bartholomew et al , 1991; Chang and Walling, 1991; Weatherwax et al , 1996; Staneloni et al , 2008). However, it remains unknown whether the decline of plant stress tolerance due to a lack of the LHCB proteins is associated with the plant response to ABA under environmental stresses.…”

The effect of cold priming on the fitness of Arabidopsis thaliana accessions under natural and controlled conditions

“…by the extent of photosynthetic carbon assimilation, which also impacts on the reproductive fitness3435. In Arabidopsis, the leaves expand strongest between the 8-leaves-stage (stage 1.0836) and bolting (stage 536).…”

Arabidopsis ANGULATA10 is required for thylakoid biogenesis and mesophyll development

“…9A). Because the LHCB5 gene is known to be overexpressed in plants that do not express the LHCB1 and LHCB2 proteins (Ruban et al , 2003), the expression of LHCB5 was also analysed. However, the expression levels of LHCB5 were not significantly different in anu10-1 and L er (Fig.…”

“…A lower amount of LHCII trimers in anu10-1 thylakoids was detected here, in line with the proposed role of trimeric LHCII complexes in thylakoid stacking. Reduced levels of LHCII trimers in the gdc1-3 mutant have been linked to impaired grana stacking in Arabidopsis (Cui et al , 2011), and other authors have shown that normal thylakoid stacking can still occur in plants with reduced levels of LHCB1 and LHCB2 (Andersson et al , 2003), which are compensated by higher levels of LHCB5 (Ruban et al , 2003). Stacks of thylakoidal membranes have been found in other mutants with reduced levels of LHCB transcripts, such as genomes uncoupled1 ( gun1 ) (Susek et al , 1993), immutans (Wetzel et al , 1994), and CAB underexpressed4 (cue4) and cue9 (Lopez-Juez et al , 1998).…”