Cytokinins and Abscisic Acid Regulate the Expression of the Genes for Plastid Transcription Apparatus during Heat Shock

2019 ◽  
Vol 486 (1) ◽  
pp. 108-113
Author(s):  
A. A. Andreeva ◽  
I. A. Bychkov ◽  
M. N. Danilova ◽  
N. V. Kudryakova ◽  
V. V. Kusnetsov

The treatment of Arabidopsis thaliana plants with exogenous cytokinin (CK) followed by heat shock (HS) activated the expression of the genes for the plastid transcription machinery but adversely affected the plant viability. Abscisic acid (ABA), conversely, promoted maintaining the resistance to HS and had differentially affected different components of the plastid transcriptional complex. This hormone suppressed the accumulation of transcripts of PEP genes and the genes encoding PAP proteins, which are involved in DNA-RNA metabolism. However, it had no effect or activated the expression of NEP genes and PAP genes, which are involved in the redox regulation, as well as the genes encoding the stress-inducible trans-factor (SIG5) and the plastid transcription Ser/Thr protein kinase (spCK2). Thus, for the adaptation of plants to elevated temperatures, both increase and decrease in the expression of the genes for the plastid transcriptional machinery with the involvement of various regulatory systems, including phytohormones, are equally significant.

Botany ◽  
2017 ◽  
Vol 95 (1) ◽  
pp. 9-27 ◽  
Author(s):  
Gillian Halter ◽  
Nicole Simonetti ◽  
Cristy Suguitan ◽  
Kenneth Helm ◽  
Jessica Soroksky ◽  
...  

Thermotolerance is a property of all organisms, but owing to their sessile nature, this trait is particularly important in plants. Basal thermotolerance is based on inherent tolerance to heat stress. Acquired thermotolerance is attained through stress-induced gene expression, often of those genes encoding heat shock proteins (HSPs). Both basal and acquired thermotolerance have been extensively studied in model species such as Arabidopsis thaliana (L.) Heynh., but much less is known about thermotolerance in wild plant species. The aims of this study were to examine the basal and acquired thermotolerance of four species of Boechera, and of A. thaliana. Four species of Boechera native to California were collected and used for this study: B. arcuata (Nutt.) Windham & Al-Shehbaz, B. californica (Rollins) Windham & Al-Shehbaz, B. depauperata (A.Nelson & P.B.Kenn.) Windham & Al-Shehbaz, and B. perennans (S.Watson) W.A.Weber. Seedlings were exposed to both basal and acquired heat stress and then monitored for leaf damage, chlorophyll fluorescence, and gene expression of HsfA3, Hsp101, and four sHSP genes. Analysis of organismal responses to heat stress demonstrated that all four Boechera species are more thermotolerant than A. thaliana. Further we found that he species with the highest thermotolerance is B. depauperata.


Plants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 323 ◽  
Author(s):  
Imene Toumi ◽  
Marianthi G. Pagoulatou ◽  
Theoni Margaritopoulou ◽  
Dimitra Milioni ◽  
Kalliopi A. Roubelakis-Angelakis

The chaperones, heat shock proteins (HSPs), stabilize proteins to minimize proteotoxic stress, especially during heat stress (HS) and polyamine (PA) oxidases (PAOs) participate in the modulation of the cellular homeostasis of PAs and reactive oxygen species (ROS). An interesting interaction of HSP90s and PAOs was revealed in Arabidopsis thaliana by using the pLFY:HSP90RNAi line against the four AtHSP90 genes encoding cytosolic proteins, the T-DNA Athsp90-1 and Athsp90-4 insertional mutants, the Atpao3 mutant and pharmacological inhibitors of HSP90s and PAOs. Silencing of all cytosolic HSP90 genes resulted in several-fold higher levels of soluble spermidine (S-Spd), acetylated Spd (N8-acetyl-Spd) and acetylated spermine (N1-acetyl-Spm) in the transgenic Arabidopsis thaliana leaves. Heat shock induced increase of soluble-PAs (S-PAs) and soluble hydrolyzed-PAs (SH-PAs), especially of SH-Spm, and more importantly of acetylated Spd and Spm. The silencing of HSP90 genes or pharmacological inhibition of the HSP90 proteins by the specific inhibitor radicicol, under HS stimulatory conditions, resulted in a further increase of PA titers, N8-acetyl-Spd and N1-acetyl-Spm, and also stimulated the expression of PAO genes. The increased PA titers and PAO enzymatic activity resulted in a profound increase of PAO-derived hydrogen peroxide (H2O2) levels, which was terminated by the addition of the PAO-specific inhibitor guazatine. Interestingly, the loss-of-function Atpao3 mutant exhibited increased mRNA levels of selected AtHSP90 genes. Taken together, the results herein reveal a novel function of HSP90 and suggest that HSP90s and PAOs cross-talk to orchestrate PA acetylation, oxidation, and PA/H2O2 homeostasis.


2019 ◽  
Vol 486 (1) ◽  
pp. 163-167
Author(s):  
A. A. Andreeva ◽  
I. A. Bychkov ◽  
M. N. Danilova ◽  
N. V. Kudryakova ◽  
V. V. Kusnetsov

Author(s):  
L.Ye. Kozeko ◽  
◽  
E.L. Kordyum ◽  

Mitochondrial heat shock proteins of HSP70 family support protein homeostasis in mitochondria under normal and stress conditions. They provide folding and complex assembly of proteins encoded by mitochondrial genome, as well as import of cytosolic proteins to mitochondria, their folding and protection against aggregation. There are reports about organ-specificity of mitochondrial HSP70 synthesis in plants. However, tissue specificity of their functioning remains incompletely characterized. This problem was studied for mitochondrial AtHSP70-10 in Arabidopsis thaliana seedlings using a transgenic line with uidA signal gene under normal conditions, as well as high temperature and water deficit. Under normal conditions, histochemical GUS-staining revealed the expression of AtHSP70-10 in cotyledon and leaf hydathodes, stipules, central cylinder in root differentiation and mature zones, as well as weak staining in root apex and root-shoot junction zone. RT-PCR analysis of wild-type seedlings exposed to 37°C showed rapid upregulation of AtHSP70-10, which reached the highest level within 2 h. In addition, the gradual development of water deficit for 5 days caused an increase in transcription of this gene, which became more pronounced after 3 days and reached a maximum after 5 days of dehydration. Histochemical analysis showed complete preservation of tissue localization of AtHSP70-10 expression under both abiotic factors. The data obtained indicate the specific functioning of mitochondrial chaperone AtHSP70-10 in certain plant cellular structures.


2011 ◽  
Vol 49 (3) ◽  
pp. 357-362 ◽  
Author(s):  
Sophie Paradis ◽  
Ana Laura Villasuso ◽  
Susana Saez Aguayo ◽  
Régis Maldiney ◽  
Yvette Habricot ◽  
...  

2021 ◽  
Vol 19 (1) ◽  
pp. 44-57
Author(s):  
Sirine Werghi ◽  
Charfeddine Gharsallah ◽  
Nishi Kant Bhardwaj ◽  
Hatem Fakhfakh ◽  
Faten Gorsane

AbstractDuring recent decades, global warming has intensified, altering crop growth, development and survival. To overcome changes in their environment, plants undergo transcriptional reprogramming to activate stress response strategies/pathways. To evaluate the genetic bases of the response to heat stress, Conserved DNA-derived Polymorphism (CDDP) markers were applied across tomato genome of eight cultivars. Despite scattered genotypes, cluster analysis allowed two neighbouring panels to be discriminate. Tomato CDDP-genotypic and visual phenotypic assortment permitted the selection of two contrasting heat-tolerant and heat-sensitive cultivars. Further analysis explored differential expression in transcript levels of genes, encoding heat shock transcription factors (HSFs, HsfA1, HsfA2, HsfB1), members of the heat shock protein (HSP) family (HSP101, HSP17, HSP90) and ascorbate peroxidase (APX) enzymes (APX1, APX2). Based on discriminating CDDP-markers, a protein functional network was built allowing prediction of candidate genes and their regulating miRNA. Expression patterns analysis revealed that miR156d and miR397 were heat-responsive showing a typical inverse relation with the abundance of their target gene transcripts. Heat stress is inducing a set of candidate genes, whose expression seems to be modulated through a complex regulatory network. Integrating genetic resource data is required for identifying valuable tomato genotypes that can be considered in marker-assisted breeding programmes to improve tomato heat tolerance.


2021 ◽  
Author(s):  
Jiuxiao Ruan ◽  
Huhui Chen ◽  
Tao Zhu ◽  
Yaoguang Yu ◽  
Yawen Lei ◽  
...  

Abstract In flowering plants, repression of the seed maturation program is essential for the transition from the seed to the vegetative phase, but the underlying mechanisms remain poorly understood. The B3-domain protein VIVIPAROUS1/ABSCISIC ACID-INSENSITIVE3-LIKE 1 (VAL1) is involved in repressing the seed maturation program. Here we uncovered a molecular network triggered by the plant hormone brassinosteroid (BR) that inhibits the seed maturation program during the seed-to-seedling transition in Arabidopsis (Arabidopsis thaliana). val1-2 mutant seedlings treated with a BR biosynthesis inhibitor form embryonic structures, whereas BR signaling gain-of-function mutations rescue the embryonic structure trait. Furthermore, the BR-activated transcription factors BRI1-EMS-SUPPRESSOR 1 and BRASSINAZOLE-RESISTANT 1 bind directly to the promoter of AGAMOUS-LIKE15 (AGL15), which encodes a transcription factor involved in activating the seed maturation program, and suppress its expression. Genetic analysis indicated that BR signaling is epistatic to AGL15 and represses the seed maturation program by downregulating AGL15. Finally, we showed that the BR-mediated pathway functions synergistically with the VAL1/2-mediated pathway to ensure the full repression of the seed maturation program. Together, our work uncovered a mechanism underlying the suppression of the seed maturation program, shedding light on how BR promotes seedling growth.


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