Turnover of dysfunctional organelles is vital to maintain homeostasis in eukaryotic cells. As photosynthetic organelles, plant chloroplasts can suffer sunlight-induced damage. However, the process for turnover entire damaged remains unclear. Here, we demonstrate that autophagy responsible elimination sunlight-damaged, collapsed Arabidopsis thaliana We found vacuolar transport chloroplasts, termed chlorophagy, was induced by UV-B damage chloroplast apparatus. This did not occur...

The amounts of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), total chlorophyll (Chl), and leaf nitrogen were measured in fully expanded, young leaves wheat (Triticum aestivum L.), rice (Oryza sativa spinach (Spinacia oleracea bean (Phaseolus vulgaris pea (Pisum sativum L.). In addition, the activities whole-chain electron transport carbonic anhydrase measured. All plants grown hydroponically at different concentrations. Although a greater than proportional increase Rubisco...

Abstract Autophagy is an intracellular process leading to the vacuolar degradation of cytoplasmic components. Autophagic chloroplasts particularly activated in leaves under conditions low sugar availability. Here, we investigated importance autophagy energy availability and growth Arabidopsis (Arabidopsis thaliana). autophagy-deficient (atg) mutants showed reduced short-day conditions. This inhibition was largely relieved continuous light or combined with feeding exogenous sucrose,...

Plant chloroplasts constantly accumulate damage caused by visible wavelengths of light during photosynthesis. Our previous study revealed that entire photodamaged are subjected to vacuolar digestion through an autophagy process termed chlorophagy; however, how this is induced and executed remained poorly understood. In study, we monitored intracellular induction chlorophagy in Arabidopsis (Arabidopsis thaliana) leaves found mesophyll cells damaged high displayed abnormal with a swollen shape...

Autophagy is an intracellular process leading to vacuolar or lysosomal degradation of cytoplasmic components in eukaryotes. Establishment proper methods monitor autophagy was a key step uncovering its role organisms, such as yeast (Saccharomyces cerevisiae), mammals, and Arabidopsis (Arabidopsis thaliana), which chloroplastic proteins were found be recycled by autophagy. Chloroplast recycling has been predicted function nutrient remobilization for growing organs grain filling cereal crops....

Autophagy and the ubiquitin-proteasome system are major degradation processes for intracellular components in eukaryotes. Although ubiquitination acts as a signal inducing organelle-targeting autophagy, interaction between autophagy chloroplast turnover has not been addressed. In this study, we found that two chloroplast-associated E3 enzymes, SUPPRESSOR OF PPI1 LOCUS1 PLANT U-BOX4 (PUB4), necessary induction of either piecemeal stroma or chlorophagy whole damaged chloroplasts Arabidopsis (

Abstract In autophagy, cytoplasmic components of eukaryotic cells are transported to lysosomes or the vacuole for degradation. Autophagy is involved in plant tolerance photooxidative stress caused by ultraviolet B (UVB) radiation, but its roles adaptation UVB damage have not been fully elucidated. Here, we characterized organellar behavior UVB-damaged Arabidopsis (Arabidopsis thaliana) leaves and observed occurrence autophagic elimination dysfunctional mitochondria, a process termed...

Effects of irradiance on photosynthetic characteristics were examined in senescent leaves rice (Oryza sativa L.). Two treatments (100 and 20% natural sunlight) imposed after the full expansion 13th leaf through senescence. The rate was measured as a function intercellular CO(2) pressure with gas-exchange system. amounts cytochrome f, coupling factor 1, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), chlorophyll determined. 1 f contents decreased rapidly during senescence, their...

Summary Rice cultivars vary widely in their sensitivity to ultraviolet B (UVB) and this has been correlated with cyclobutane pyrimidine dimer (CPD) photolyase mutations that alter the structure/function of photorepair enzyme. Here, we tested whether CPD function determines UVB rice ( Oryza sativa ) by generating transgenic plants bearing gene UV‐resistant cultivar Sasanishiki sense orientation (S‐B S‐C lines) or antisense (AS‐D line). The S‐B had 5.1‐ 45.7‐fold higher activities than...

Plants use sunlight as energy for photosynthesis; however, plant DNA is exposed to the harmful effects of ultraviolet-B (UV-B) radiation (280-320 nm) in process. UV-B damages nuclear, chloroplast and mitochondrial by formation cyclobutane pyrimidine dimers (CPDs), which are primary UV-B-induced lesions, a principal cause growth inhibition plants. Repair CPDs therefore essential survival while UV-B-containing sunlight. Nuclear repair involves photoreversal CPDs, photoreactivation, mediated...

Plants have evolved various mechanisms that protect against the harmful effects of UV-B radiation (280–315 nm) on growth and development. Cyclobutane pyrimidine dimer (CPD) photolyase, repair enzyme for UV-B-induced CPDs, is essential protecting cells from radiation. Expression CPD photolyase gene ( PHR ) controlled by light with wavelengths including UV-B, but this regulation remain poorly understood. In study, we investigated expression wavelengths, in particular low-fluence (280 nm, 0.2...

Changes in carbon fixation rate and the levels of photosynthetic proteins were measured fourth leaves Lolium temulentum grown until full expansion at 360 μmol quanta m−2 s−1 subsequently same irradiance or shaded to 90 s−1. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), light-harvesting chlorophyll a/b protein photosystem II (LHCII), 65 kDa I (PSI), cytochrome f (Cytf) coupling factor 1 (CF1) declined steadily amount throughout senescence unshaded leaves. In leaves, however,...

UV-B responses of three rice (Oryza sativa L.) cultivars (Sasanishiki, Norin 1 and Surjamkhi) with different photolyase activity were investigated. Carbon dioxide assimilation data support that Sasanishiki was less sensitive to than Surjamkhi. radiation sharply decreased the content Rubisco protein in Surjamkhi has no effect Sasanishiki. The photochemical activities photosystem (PS) PS 2 slightly affected by treatment. H2O2 antioxidant enzymes, catalase (CAT), peroxides (POX) superoxide...

Sensitivity to ultraviolet-B (UVB, 280-315 nm) radiation varies widely among rice (Oryza sativa) cultivars due differences in the activity of cyclobutane pyrimidines dimer (CPD) photolyase. Interestingly, with high UVB sensitivity and low CPD photolyase have been domesticated tropical areas radiation. Here, we investigated how affect plant resistance blast fungus, Magnaporthe oryzae, which is one other major stresses. We used Asian African transgenic lines different activities evaluate...

Norin 1, a progenitor of many economically important Japanese rice strains, is highly sensitive to the damaging effects UVB radiation (wavelengths 290 320 nm). 1 seedlings are deficient in photorepair cyclobutane pyrimidine dimers. However, molecular origin this deficiency was not known and, because photolyase genes have been cloned and sequenced, could be determined by examining structural or upstream regulatory elements for mutations. We therefore used photoflash approach, which showed...

Repair of cyclobutyl pyrimidine dimers (CPDs) in DNA is essential most organisms to prevent biological damage by ultraviolet (UV) light. In higher plants tested thus far, UV-sensitive strains had initial levels or deficient repair nondimer lesions but normal CPD repair. This suggested that CPDs might not be important for lesions. The photosynthetic apparatus has also been proposed as a critical target. We have analyzed induction and the rice (Oryza sativa L.) cultivar Norin 1 its close...

Abstract The effects of supplementary ultraviolet‐B (UV‐B) radiation on the changes in synthesis and degradation ribulose ‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) light‐harvesting chlorophyll a / b binding protein PSII (LHCII) were examined, as well mRNA levels for small large subunits Rubisco ( rbcS rbcL , respectively) LHCII cab ) with leaf age UV‐sensitive rice (Norin 1) UV‐resistant (Sasanishiki). Both actively synthesized until had fully expanded, then decreased increasing age....

Effects of irradiance on changes in the amounts chlorophyll (Chl) and light-harvesting a/b protein PS II (LHCII) were examined senescing leaves rice (Oryza sativa L.). Results treatments at two irradiances (100% 20% natural sunlight) after full expansion 13th leaf throughout course senescence. With sunlight, Chl content decreased only a little during senescence, while with 100% sunlight it appreciably. Similarly, amount LHCII treatment remained almost constant. However, ratio shade...

There is a cultivar difference in the response to ultraviolet-B (UVB: 280–320 nm) rice (Oryza sativa L.). Among Japanese lowland cultivars, Sasanishiki, leading cultivar, resistant damaging effects of UVB while Norin 1, close relative, less resistant. We found previously that 1 was deficient cyclobutane pyrimidine dimer (CPD) photorepair ability and suggested sensitivity depends largely on CPD ability. In order verify suggestion, we examined correlation between photolyase activity 17...

Lamps that emit 222 nm short-wavelength ultraviolet (UV) radiation can be safely used for sterilization without harming human health. However, there are few studies on the effects of UVC (222-UVC) exposure plants compared with germicidal lamps emitting primarily 254 (254-UVC) radiation. We investigated growth inhibition and cell damage caused by 222-UVC to Arabidopsis plants, especially mitochondrial dynamics, which is an index UVB Growth resulted from 254-UVC or depending dose respect...

The ultraviolet B (UVB) sensitivity of rice cultivated in Asia and Africa varies greatly, with African cultivars (Oryza glaberrima Steud. O. barthii A. Chev.) being more sensitive to UVB because their low cyclobutane pyrimidine dimer (CPD) photolyase activity, which is a CPD repair enzyme, relative Asian (O. sativa L.). Hence, the production UVB-resistant augmented activity great importance, although difficulty transforming this end has been reported. Here, we successfully produced...

ABSTRACT Growth of a near‐isogenic line (NIL) for the purple leaf gene Pl rice with genetic background Taichung 65 (T‐65) was significantly retarded by supplementary ultraviolet‐B radiation (UV‐B), despite fact that amounts UV‐absorbing compounds and anthocyanins in NIL were higher than those T‐65. In order to understand role flavonoids UV‐B induced damage protection T‐65 NIL, both (1) relationships between changes steady state cyclobutane pyrimidine dimer (CPD) levels accumulation leaves...