scholarly journals Chlorophyll biosynthesis and transcriptome profiles of chlorophyll b-deficient type 2b rice (Oryza sativa L.)

2021 ◽  
Vol 49 (3) ◽  
pp. 12380
Author(s):  
Minh Khiem NGUYEN ◽  
Chi-Ming Yang ◽  
Tin-Han SHIH ◽  
Szu-Hsien LIN ◽  
Giang Tuyet PHAM ◽  
...  

Photosynthetic and transcriptomic characteristics of a chlorophyll (Chl) b-deficient mutant type 2b rice (ch14) were investigated in this study. The ultrastructure of chloroplast in ch14 demonstrated irregular chloroplast enhancement (loss of starch granules, indistinct membranes, and thinner grana). Ch14 had significantly lower carotenoid, Chl a, Chl b, and total Chl contents, but a higher ratio of Chl a to Chl b than a wide-type rice. 3,594 genes were differentially expressed in ch14, among which 309 transcription factors were related to Chl degradation and biosynthesis, chloroplast formations, and the photosynthesis capacity. PsbR, GSA-AT, PBGD, PPOX, MgMT, and POR genes were down-regulated, reducing Chl content and photosynthetic capacity in the ch14. This study suggests that Chl degradation may be attributed to abnormal chloroplast development and down-regulation of gene expression in the common pathway and Mg branch and the rise in Chl a to Chl b ratio may be involved in the alternative Chl b degradation pathway.

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 401
Author(s):  
Minh Khiem Nguyen ◽  
Tin-Han Shih ◽  
Szu-Hsien Lin ◽  
Jun-Wei Lin ◽  
Hoang Chinh Nguyen ◽  
...  

Photosynthesis is an essential biological process and a key approach for raising crop yield. However, photosynthesis in rice is not fully investigated. This study reported the photosynthetic properties and transcriptomic profiles of chlorophyll (Chl) b-deficient mutant (ch11) and wild-type rice (Oryza sativa L.). Chl b-deficient rice revealed irregular chloroplast development (indistinct membranes, loss of starch granules, thinner grana, and numerous plastoglobuli). Next-generation sequencing approach application revealed that the differential expressed genes were related to photosynthesis machinery, Chl-biosynthesis, and degradation pathway in ch11. Two genes encoding PsbR (PSII core protein), FtsZ1, and PetH genes, were found to be down-regulated. The expression of the FtsZ1 and PetH genes resulted in disrupted chloroplast cell division and electron flow, respectively, consequently reducing Chl accumulation and the photosynthetic capacity of Chl b-deficient rice. Furthermore, this study found the up-regulated expression of the GluRS gene, whereas the POR gene was down-regulated in the Chl biosynthesis and degradation pathways. The results obtained from RT-qPCR analyses were generally consistent with those of transcription analysis, with the exception of the finding that MgCH genes were up-regulated which enhance the important intermediate products in the Mg branch of Chl biosynthesis. These results indicate a reduction in the accumulation of both Chl a and Chl b. This study suggested that a decline in Chl accumulation is caused by irregular chloroplast formation and down-regulation of POR genes; and Chl b might be degraded via the pheophorbide b pathway, which requires further elucidation.


2021 ◽  
Vol 49 (2) ◽  
pp. 12306
Author(s):  
Khiem Minh NGUYEN ◽  
Zhi-Wei YANG ◽  
Tin-Han SHIH ◽  
Szu-Hsien LIN ◽  
Jun-Wei LIN ◽  
...  

Extreme temperatures have become a threat to crop yields. To maintain plant growth and yield, chlorophyll (Chl) biosynthesis plays a crucial role in adaptation to temperature stress. This study investigated the influence of temperature on the biosynthesis and characteristics of pigments (Chl a, Chl b, and carotenoids) in the leaves of Chl b-lacking mutant rice (Chlorina 1, ch1) and wild-type rice (Norin No.8, wt). The ch1 showed thinner stacked grana caused by a decrease in thylakoid membranes per granum at 15 °C, whereas the destacked grana were observed at 35 °C after 12 h incubation. However, the grana are stacked normally, along with the absence of Chl b, and a significantly decreased amount of Chl a in both wt and ch1 were observed after heat stress exposure, demonstrating that light-harvesting complex II proteins are involved in grana stacking. Ch1 was sensitive to 15 °C during the first 4 h of incubation but it subsequently adapted to the cold environment. In addition, there were no significant differences in the photosynthesis between wt and ch1 after 12 h incubation at 35 °C. Differentially expressed gene (DEGs) analysis revealed that GluRS expression decreased, which resulted in a decline in Chl biosynthesis in wt and ch1 at 35 °C. At 8 h and 12 h, there were no significant differences in the expression of DEGs involved in Chl biosynthesis and degradation between wt and ch1 at 15 °C. ALAD expression in wt and ch1 at 15 °C decreased until it was undetectable. These findings suggested that ch1 may adapt to temperatures ranging from 15 °C to 35 °C.


1995 ◽  
Vol 44 (3) ◽  
pp. 221-242 ◽  
Author(s):  
Yael J. Avissar ◽  
Patricia A. Moberg

2020 ◽  
Author(s):  
Pingrong Wang ◽  
Fuliang Xiao ◽  
San Wang ◽  
Jia Guo ◽  
Qingsong Liu ◽  
...  

Abstract BackgroundThe ankyrin repeat (ANK) proteins are widely distributed in organisms ranging from viruses to plants, which play key roles in plastid differentiation, embryogenesis, chloroplast biogenesis and so on. However, only a few ANK genes have been identified in rice.ResultsIn this study, we isolated a yellow-green leaf mutant, 520ys, from japonica rice cultivar Nipponbare through ethyl methane sulfonate mutagenesis. The mutant exhibited a yellow-green leaf phenotype throughout the life cycle, arrested development of chloroplasts, reduced levels of photosynthetic pigments, and accumulated reactive oxide species. Map-based cloning suggested that the candidate gene was LOC_Os07g33660, which encodes an expressed protein containing one ankyrin repeat and showing sequence similarity with the Arabidopsis LTD/GDC1 (At1g50900). Transgenic complementation experiment confirmed that LOC_Os07g33660 is the causal gene for the mutant type of 520ys. 520YS (LOC_Os07g33660) is mainly expressed in green tissues and its encoded protein is targeted to the chloroplast. In 520ys mutant, expression levels of four light-harvesting chlorophyll a/b-binding protein translocation-related genes and eight photosynthesis-related genes were significantly down-regulated.ConclusionWe characterized a novel ANK gene, 520YS, which plays a key role in chloroplast development in rice.


1991 ◽  
Vol 42 (3) ◽  
pp. 485 ◽  
Author(s):  
T Tashiro ◽  
IF Wardlaw

Rice (Oryza sativa L. cv. Calrose) growing at 27/22�C was either transferred to day/night temperatures ranging from 24/19 to 39/34�C 7days after heading and held at these temperatures until maturity, or transferred to a temperature of 36/31�C for 8 day periods at regular intervals commencing from heading. Kernel dimensions were measured directly and the types of kernel damage at maturity were characterized by direct viewing under the light microscope of intact and sectioned kernels, or by scanning electron microscopy of the exposed surface of kernels cut transversely with a razor blade. Kernel thickness was reduced most by high temperature treatments commencing 12 days after heading, but other kernel dimensions (length and width) were most sensitive to high temperature earlier in development. Sterility and pathenocarpy were most evident when temperature treatments commenced at heading (approximately 2 days before anthesis) and were greatest at the highest temperature (39/34�C). Abortive and opaque kernels were most evident when the high temperature commenced 4 days after heading and were also most numerous at the highest temperature tested. From observations on the morphology of the kernels it appears that temperatures above 27/22�C can interfere with the early stages of cell division and development in the endosperm. Chalky endosperm tissue occurred in several forms depending on both the temperature level and the timing of the temperature treatment. White-core kernels were only evident at a temperature of 27/22�C. White-back kernels were most numerous at 36/31�C and when the high temperature treatment commenced 16 days after heading. Milky-white kernels were found in all but the lowest temperature treatment (24/19�C), with a peak at 36/31�C and this type of damage was most evident when the high temperature treatment commenced 12 days after heading. Differences in endosperm cellular morphology were observed between the different types of damage, and in accord with other published data the chalky appearance was associated with the development of numerous air spaces between loosely packed starch granules and a change in light refraction.


Plant Science ◽  
2019 ◽  
Vol 283 ◽  
pp. 11-22 ◽  
Author(s):  
Ning Yu ◽  
Qunen Liu ◽  
Yingxin Zhang ◽  
Bo Zeng ◽  
Yuyu Chen ◽  
...  

2015 ◽  
Vol 02 (01) ◽  
pp. 044-048 ◽  
Author(s):  
Anusha Doraiswamy ◽  
Bhanu Kesavamurthy ◽  
Lakshminarasimhan Ranganathan

AbstractGlutaric aciduria type 1 (GA-1) is a rare inherited neurometabolic disorder due to enzymatic block in the common degradation pathway for lysine and tryptophan. We report a 16 month girl child who presented with an initial acute encephalopathic crisis followed by static encephalopathy with characteristic neuroimaging findings. Diagnosis was confirmed by demonstrating elevated urinary glutaric acid and 3-hydroxyglutaric acid levels. Early diagnosis and adequate dietetic therapy can prevent most of the neurological symptoms.


2021 ◽  
Author(s):  
Dongzhi Lin ◽  
Licheng Kang ◽  
Wenhao Zhou ◽  
Yulu Wang ◽  
Yu Chen ◽  
...  

Abstract Transcriptionally active chromosome (TAC) is a component of protein-DNA complexes with RNA polymerase activity found in chloroplasts. Although TAC in Arabidopsis thaliana has been extensively investigated, how the rice (Oryza sativa L.) TAC complex functions remains largely unknown. We report the characterization of the mutant thermosensitive chlorophyll-deficient7 (tcd7) and the cloning of TCD7. tcd7 mutant seedlings displayed an albino phenotype specifically at low temperatures and before the four-leaf stage. We identified TCD7 by map-based cloning followed by transgenic rescue and genome editing tests, showing that TCD7 encodes the putative TAC component FRUCTOKINASE-LIKE 2 (OsFLN2). TCD7 transcripts were highly abundant in green tissues, and the protein localized to chloroplasts. In agreement with the albino phenotype, transcript levels of genes controlling chloroplast development and the establishment of photosynthetic capacity were severely reduced in tcd7 seedlings at low temperatures, but were expressed as in the wild type at high temperatures, implying that TCD7 regulates the PEP pathway and chloroplast development. Moreover, TCD7 interacted with the thioredoxin OsTRXz to form an OsTRXz-TCD7 regulatory module, which might regulate plastid transcription under cold stress. Our results demonstrate that the nucleus-encoded TAC protein TCD7 protects chloroplast development from cold stress via a TRXz-FLN regulatory module.


Author(s):  
Dongzhi Lin ◽  
Wenhao Zhou ◽  
Yulu Wang ◽  
Jia Sun ◽  
Xiaobiao Pan ◽  
...  

Abstract Threonyl-tRNA synthetase (ThrRS), one of aminoacyl-tRNA synthetases (AARSs), plays a crucial role in protein synthesis. However, the AARS functions on rice chloroplast development and growth were not fully appraised. In this study, a thermo-sensitive virescent mutant tsv2, which showed albino phenotype and lethal after the 4-leaf stage at 20 °C but recovered to normal when the temperatures rose, was identified and characterized. Map-based cloning and complementation tests showed that TSV2 encoded a chloroplast-located ThrRS protein in rice. The Lys-to-Arg mutation in the anticodon-binding domain hampered chloroplast development under cold stress, while the loss-of-function of the ThrRS core domain in TSV2 fatally led to seedling death regardless of growing temperatures. In addition, TSV2 had a specific expression in early leaves. Its disruption obviously resulted in down-regulation of certain genes associated with chlorophyll biosynthesis, photosynthesis and chloroplast development at cold conditions. Our observations revealed that rice nuclear-encoded TSV2 plays an important role in chloroplast development at the early leaf stage under cold stress.


2018 ◽  
Vol 4 (4) ◽  
pp. 311-313
Author(s):  
Sasmita Kumari Behura ◽  
Mamata Mohapatra ◽  
B.K. Mohanty

Plants exposed to zinc stress at high concentration inhibit seed germination, seedling growth and development. The germination data showed that there is a negative impact of concentration of zinc sulphate on the germination of seeds. Root and shoot growth of seedlings was worse affected when exposed to higher concentration on ZnSO4. Shoots were more affected than roots. Morphologically they look different from normal roots by their shape and size. Zn toxicity inhibits the chlorophyll formation and with the increase in concentration of the toxicant the exposed seedlings showed a decline in chl-a (chlorophyll-a), chl-b (chlorophyll – b) and total chlorophyll pigment content. Conclusively, our result shows that zinc sulphate at higher concentration decreases seed germination, chl-a, chl-b and total chlorophyll content and also decreases root and shoot growth of plants.


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