OsCER1 Plays a Pivotal Role in Very-Long-Chain Alkane Biosynthesis and Affects Plastid Development and Programmed Cell Death of Tapetum in Rice (Oryza sativa L.)

Abstract Most pentatricopeptide repeat (PPR) proteins localize to plastids or mitochondria, where they participate in RNA metabolism and post-transcriptionally regulate organelle gene expression. However, whether PPR proteins regulate the expression of nucleus-encoded genes remains unclear. Here, we uncovered a function for the rice (Oryza. sativa L.) PPR protein OsPPR2-1 (Os02g0110400) in pollen development and showed that, in contrast to most other PPR proteins, OPPR2-1 resides in the cytoplasm. Downregulating OsPPR2-1 expression led to abnormal plastid development in tapetal cells, prolonged programmed cell death (PCD), prolonged tapetum degradation, and significantly reduced pollen fertility. Transcriptome analysis revealed that the expression of OsGOLDEN-LIKE 1 (OsGLK1), encoding a transcription factor that regulates plastid development and maintenance, was significantly higher in plants with downregulated OsPPR2-1 expression compared to the wild type. Moreover, OsPPR2-1 bound to the OsGLK1 mRNA in RNA immunoprecipitation and RNA-electrophoretic mobility shift assays. An in vitro cleavage assay showed that OsPPR2-1 could degrade the OsGLK1 mRNA. Notably, knockdown of OsGLK1 partially restored pollen fertility in OsPPR2-1-knockdown plants and OsGLK1-overexpressing plants showed abnormal tapetum and plastid development, similar to the OsPPR2-1-knockdown plants. Together, our findings demonstrate that OsPPR2-1 regulates OsGLK1 expression, thereby controlling plastid development and PCD in the tapetum.

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HCAR Is a Limitation Factor for Chlorophyll Cycle and Chlorophyll b Degradation in Chlorophyll-b-Overproducing Plants

Biomolecules ◽

10.3390/biom10121639 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1639

Author(s):

Xuan Zhao ◽

Ting Jia ◽

Xueyun Hu

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Metabolic Pathway ◽

Pivotal Role ◽

Limiting Factor ◽

Chlorophyll B ◽

Green Color ◽

Chl A ◽

Cycle Regulation

The chlorophyll (Chl) cycle is the metabolic pathway for Chl a and Chl b inter-conversion. In this pathway, Chl b is synthesized from Chl a by the catalyzing action of chlorophyllide a oxygenase (CAO). In contrast, Chl b is firstly reduced to produce 7-hydroxymethyl Chl (HMChl) a, which is catalyzed by two isozymes of Chl b reductase (CBR), non-yellow coloring 1 (NYC1) and NYC1-like (NOL). Subsequently, HMChl a is reduced to Chl a by HMChl a reductase (HCAR). CAO plays a pivotal role in Chl a/b ratio regulation and plants over-accumulate Chl b in CAO-overexpressing plants. NYC1 is more accumulated in Chl-b-overproducing plants, while HCAR is not changed. To investigate the role of HCAR in Chl cycle regulation, the Chl metabolites of Chl-b-overproducing plants were analyzed. The results showed that HMChl a accumulated in these plants, and it decreased and the Chl a/b ratio increased by overexpressing HCAR, implying HCAR is insufficient for Chl cycle in Chl-b-overproducing plants. Furthermore, during dark-induced senescence, the non-programmed cell death symptoms (leaves dehydrated with green color retained) of Chl-b-overproducing plants were obviously alleviated, and the content of HM pheophorbide (HMPheide) a and Pheide b were sharply decreased by overexpressing HCAR. These results imply that HCAR is also insufficient for Chl degradation in Chl-b-overproducing plants during senescence, thus causing the accumulation of Chl metabolites and non-programmed cell death of leaves. With these results taken together, we conclude that HCAR is not well regulated and it is a limiting factor for Chl cycle and Chl b degradation in Chl-b-overproducing plants.

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Organized Disassembly of Photosynthesis During Programmed Cell Death Mediated By Long Chain Bases

Scientific Reports ◽

10.1038/s41598-020-65186-8 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Alonso Zavafer ◽

Ariadna González-Solís ◽

Silvia Palacios-Bahena ◽

Mariana Saucedo-García ◽

Cinthya Tapia de Aquino ◽

...

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Long Chain

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Black Rice (Oryza sativa L ., Poaceae) Extract Reduces Hippocampal Neuronal Cell Death Induced by Transient Global Cerebral Ischemia in Mice

Experimental Neurobiology ◽

10.5607/en.2018.27.2.129 ◽

2018 ◽

Vol 27 (2) ◽

pp. 129-138 ◽

Cited By ~ 4

Author(s):

Sun-Nyoung Hwang ◽

Jae-Cheon Kim ◽

Mohammad Iqbal Hossain Bhuiyan ◽

Joo Youn Kim ◽

Ji Seon Yang ◽

...

Keyword(s):

Cell Death ◽

Oryza Sativa ◽

Cerebral Ischemia ◽

Oryza Sativa L ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Global Cerebral Ischemia ◽

Black Rice ◽

Transient Global Cerebral Ischemia

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Hygromycin B-induced cell death is partly mediated by reactive oxygen species in rice (Oryza sativa L.)

Plant Molecular Biology ◽

10.1007/s11103-015-0380-4 ◽

2015 ◽

Vol 89 (6) ◽

pp. 577-588 ◽

Cited By ~ 4

Author(s):

Hui-Min Oung ◽

Ke-Chun Lin ◽

Tsung-Meng Wu ◽

Nulu Naga Prafulla Chandrika ◽

Chwan-Yang Hong

Keyword(s):

Reactive Oxygen Species ◽

Cell Death ◽

Oryza Sativa ◽

Oryza Sativa L ◽

Reactive Oxygen ◽

Hygromycin B ◽

Oxygen Species

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Cortical cell death, cell proliferation, macromolecular movements and rTip1 expression pattern in roots of rice ( Oryza sativa L.) under NaCl stress

Planta ◽

10.1007/s004250050492 ◽

1999 ◽

Vol 207 (3) ◽

pp. 354-361 ◽

Cited By ~ 17

Author(s):

P. K. Samarajeewa ◽

R. A. Barrero ◽

C. Umeda-Hara ◽

M. Kawai ◽

H. Uchimiya

Keyword(s):

Cell Proliferation ◽

Cell Death ◽

Oryza Sativa ◽

Expression Pattern ◽

Oryza Sativa L ◽

Cortical Cell ◽

Nacl Stress

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Programmed cell death during microgenesis in a Honglian CMS line of rice is correlated with oxidative stress in mitochondria

Functional Plant Biology ◽

10.1071/fp03224 ◽

2004 ◽

Vol 31 (4) ◽

pp. 369 ◽

Cited By ~ 59

Author(s):

Shaoqing Li ◽

Cuixiang Wan ◽

Jin Kong ◽

Zaijun Zhang ◽

Yangsheng Li ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Programmed Cell Death ◽

Oryza Sativa L ◽

Inner Mitochondrial Membrane ◽

Pollen Abortion ◽

Chronic Oxidative Stress ◽

Excess Production ◽

Cms Line ◽

And Oxidative Stress

The key role of mitochondria in the integration of apoptosis and oxidative stress in mammals has been documented. In plants, mitochondria are implicated in cytoplasmic male sterility (CMS), programmed cell death (PCD), and oxidative stress. However, to date there has been no evidence presented of the interplay among CMS, PCD and oxidative stress. In this study, we demonstrate that the pollen abortion of Honglian CMS line of rice (Oryza sativa L.) displays a PCD phenotype. A premature loss of microspores was accompanied by several biochemical markers of apoptosis. Analysis of mitochondria revealed that during the PCD process there was disruption of the inner mitochondrial membrane potential in microspores. This disruption was correlated with excess production of reactive oxygen species and down-regulation of the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase in mitochondria. The excess accumulation of ROS spanned three stages from pollen mother cell to early-uninucleate stage, and was followed by the occurrence of PCD at meiosis. Our data suggest that the microspores suffered from severe oxidative stress during pollen development. It is likely the chronic oxidative stress triggered the tissue-specific PCD and consequently resulted in the abortion of microspores.

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