Comparative proteomic analysis of autotetraploid and diploid Paulownia tomentosa reveals proteins associated with superior photosynthetic characteristics and stress adaptability in autotetraploid Paulownia

In Vitro Inducted Tetraploid Elsholtzia splendens Nakai ex F. Maek. Alters Polyphenol Species and Synthesis

Elsholtzia splendens Nakai ex F. Maek. has been employed in traditional Chinese medicine for millennia. Nevertheless, the small size and the paucity of research on its pharmacological effects have restricted its extensive utilisation in clinical medicine. Polyploid breeding represents an effective method for the rapid enhancement of plant biomass and metabolites. In this study, the most effective in vitro method for inducing tetraploid formation was identified as axillary buds treated in a solution of colchicine at a concentration of 1% for 24 h. Meanwhile, a comparison between tetraploids and diploids yielded two significant findings: (1) The presence of 6-zonocolpate and 8-zonocolpate pollen grains can be used as distinguishing characteristics for diploid and tetraploid, respectively. (2) Genome duplication resulted in alterations to the polyphenol species and synthesis pathway in E. splendens. The accumulation of wogonin, oroxylin A, baicalin, chrysin, acacetin and related derivatives was markedly greater in tetraploid plants, whereas apigenin, naringenin, scutellarein and related derivatives were found to accumulate to a greater extent in diploid plants. It is noteworthy that wogonin and oroxylin A were uniquely detected in tetraploids, indicating that the generated tetraploids may harbor novel pharmacological value. The findings not only provided new insights into the metabolic mechanism of polyploidisation but also established a foundation for the selection and breeding of novel genetic resources of E. splendens.

Acetylome reprograming participates in the establishment of fruit metabolism during polyploidization in citrus

Polyploidization leads to novel phenotypes and is a major force in evolution. However, the relationship between the evolution of new traits and variations in the post-translational modifications (PTM) of proteins during polyploidization has not been studied. Acetylation of lysine residues is a common protein PTM that plays a critical regulatory role in central metabolism. To test whether changes in metabolism in citrus fruit is associated with the reprogramming of lysine acetylation (Kac) in non-histone proteins during allotetraploidization, we performed a global acetylome analysis of fruits from a synthetic allotetraploid citrus and its diploid parents. A total of 4,175 Kac sites were identified on 1,640 proteins involved in a wide range of fruit traits. In the allotetraploid, parental dominance (i.e. resemblance to one of the two parents) in specific fruit traits, such as fruit acidity and flavonol metabolism, was highly associated with parental Kac level dominance in pertinent enzymes. This association is due to Kac-mediated regulation of enzyme activity. Moreover, protein Kac probably contributes to the discordance between the transcriptomic and proteomic variations during allotetraploidization. The acetylome reprogramming can be partially explained by the expression pattern of several lysine deacetylases (KDACs). Overexpression of silent information regulator 2 (CgSRT2) and histone deacetylase 8 (CgHDA8) diverted metabolic flux from primary metabolism to secondary metabolism and partially restored a metabolic status to the allotetraploid, which expressed attenuated levels of CgSRT2 and CgHDA8. Additionally, KDAC inhibitor treatment greatly altered metabolism in citrus fruit. Collectively, these findings reveal the important role of acetylome reprogramming in trait evolution during polyploidization.

The Role of Melanin in the Biology and Ecology of Nematophagous Fungi

Melanin is a heteropolymer formed by the polymerization of phenolic and indolic compounds. It occurs in organisms across all biological kingdoms and has a range different of functions, thus indicating its important evolutionary role. The presence of melanin offers several protective advantages, including against ultraviolet radiation, traumatic damage, oxidative stress, extreme temperatures, and pressure. For many species of fungi, melanin also participates directly in the process of virulence and pathogenicity. These organisms can synthesize melanin in two main ways: using a substrate of endogenous origin, involving 1,8-dihydroxynaphthalene (DHN); alternatively, in an exogenous manner with the addition of L-3, 4-dihydroxyphenylalanine (L-DOPA or levodopa). As melanin is an amorphous and complex substance, its study requires expensive and inaccessible technologies and analyses are often difficult to perform with conventional biochemical techniques. As such, details about its chemical structure are not yet fully understood, particularly for nematophagous fungi that remain poorly studied. Thus, this review presents an overview of the different types of melanin, with an emphasis on fungi, and discusses the role of melanin in the biology and ecology of nematophagous fungi.

Proteomic analysis on the regulation of DOPA-melanin synthesis in Talaromyces marneffei

BACKGROUND

Yeast form of T.marneffei can produce DOPA-melanin which perform an important role in the pathogen surviving in macrophage. So far, the proteomic associated with melanin synthesis remain unclearly in T.marneffei.

METHODS

The whole yeast cell proteins were extracted from T.marneffei cultured with or without l-DOPA. Using two-dimensional gel electrophoresis combined with MALDI-TOF mass spectrometry, distinguished proteins were identified between T.marneffei cultured with or without l-DOPA. Furthermore, geldanamycin were used to assess the inhibition effect on T.marneffei melanin production in vitro.

RESULTS

16 distinguished proteins were identified in DOPA-melanized yeast cells, as well as 15 triple-up-expressed proteins and 7 triple-down-expressed proteins in comparison with non DOPA-melanized yeast cells. Of note, proteins differentially expressed proteins were predominantly heat shock proteins. HSP90/60/70 genes expressions increased significantly demonstrated by q-RT-PCR, which was consistent with the proteomics changes. GO analysis showed that the majority of differentially expressed proteins including HSPs(especially HSP90) were found enriched in stress response, cellular process, protein folding, stimuli response and biological process. KEGG pathway analysis showed that proteins were enriched predominantly in phagosome. HSP90 inhibitor(Geldanamycin) inhibited the brown-black pigment production of T.marneffei yeast grown on brain heart infusion agar, as well as the inhibition effect was observed by transmission electron microscope.

CONCLUSIONS

The results demonstrates that HSP90 palys an essential role in T.marneffei DOPA-melanin synthesis pathway.

The photo-inhibition of camphor leaves (Cinnamomum camphora L.) by NaCl stress based on physiological, chloroplast structure and comparative proteomic analysis

Background

The distribution and use of camphor (Cinnamomum camphora L.) trees are constrained by increasing soil salinity in south-eastern China along the Yangtze River. However, the response mechanism of this species to salinity, especially in team of photosynthesis, are unknown.

Methods

Here, we analysed themorphological, physiological, ultrastructural, and proteomic traits of camphor seedlings under NaCl (103.45 mM) treatment in pot experiments for 80 days.

Results

The growth was limited because of photosynthetic inhibition, with the most significant disturbance occurring within 50 days. Salinity caused severe reductions in the leaf photosynthetic rate (A_n), stomatal conductance (g_s), maximal chlorophyll fluorescence (F_m), maximum quantum yield of PSII (F_v/F_m), non-photochemical quenching (NPQ), relative quantum efficiency of PSII photochemistry (ΦPSII), photochemical quenching coefficient (qP) and photo-pigment contents (chlorophyll a (Cha), chlorophyll b (Chb), total chlorophyll (Chl)); weakened the antioxidant effects, including those of malondialdehyde (MDA), superoxide dismutase (SOD) and peroxidase (POD); and injured chloroplasts. The physiologicalresults indicated that the main reason for photo-inhibition was oxidative factors induced by NaCl. The proteomic results based on isobaric tags for relative and absolute quantitation (iTRAQ) further confirmedthat photosynthesis was the most significant disrupted process by salinity (P < 0.01) and there were 30 downregulated differentially expression proteins (DEPs) and one upregulated DEP related to restraint of the photosynthetic system, which affected photosystem I, photosystem II, the Cytochrome b6/f complex, ATP synthase and the light-harvesting chlorophyll protein complex. In addition, 57 DEPs were related to photo-inhibition by redox effect and 6 downregulated DEPs, including O2 evolving complex 33kD family protein (gi—224094610) and five other predicted proteins (gi—743921083, gi—743840443, gi—743885735, gi—743810316 and gi—743881832) were directly affected. This study provides new proteomic information and explains the possible mechanisms of photo-inhibition caused by salinity on C. camphor.

Gene Balance Predicts Transcriptional Responses Immediately Following Ploidy Change in Arabidopsis thaliana

The gene balance hypothesis postulates that there is selection on gene copy number (gene dosage) to preserve the stoichiometric balance among interacting proteins. This presupposes that gene product abundance is governed by gene dosage and that gene dosage responses are consistent for interacting genes in a dosage-balance-sensitive network or complex. Gene dosage responses, however, have rarely been quantified, and the available data suggest that they are highly variable. We sequenced the transcriptomes of two synthetic autopolyploid accessions of Arabidopsis (Arabidopsis thaliana) and their diploid progenitors, as well as one natural tetraploid and its synthetic diploid produced via haploid induction, to estimate transcriptome size and dosage responses immediately following ploidy change. Similar to what has been observed in previous studies, overall transcriptome size does not exhibit a simple doubling in response to genome doubling, and individual gene dosage responses are highly variable in all three accessions, indicating that expression is not strictly coupled with gene dosage. Nonetheless, putatively dosage balance-sensitive gene groups (Gene Ontology terms, metabolic networks, gene families, and predicted interacting proteins) exhibit smaller and more coordinated dosage responses than do putatively dosage-insensitive gene groups, suggesting that constraints on dosage balance operate immediately following whole-genome duplication and that duplicate gene retention patterns are shaped by selection to preserve dosage balance.

Synthetic Polyploidy in Grafted Crops

Synthetic polyploids have been extensively studied for breeding in the last decade. However, the use of such genotypes at the agronomical level is still limited. Polyploidization is known to modify certain plant phenotypes, while leaving most of the fundamental characteristics apparently untouched. For this reason, polyploid breeding can be very useful for improving specific traits of crop varieties, such as quality, yield, or environmental adaptation. Nevertheless, the mechanisms that underlie polyploidy-induced novelty remain poorly understood. Ploidy-induced phenotypes might also include some undesired effects that need to be considered. In the case of grafted or composite crops, benefits can be provided both by the rootstock's adaptation to the soil conditions and by the scion's excellent yield and quality. Thus, grafted crops provide an extraordinary opportunity to exploit artificial polyploidy, as the effects can be independently applied and explored at the root and/or scion level, increasing the chances of finding successful combinations. The use of synthetic tetraploid (4x) rootstocks may enhance adaptation to biotic and abiotic stresses in perennial crops such as apple or citrus. However, their use in commercial production is still very limited. Here, we will review the current and prospective use of artificial polyploidy for rootstock and scion improvement and the implications of their combination. The aim is to provide insight into the methods used to generate and select artificial polyploids and their limitations, the effects of polyploidy on crop phenotype (anatomy, function, quality, yield, and adaptation to stresses) and their potential agronomic relevance as scions or rootstocks in the context of climate change.

Cytological and proteomic analyses of floral buds reveal an altered atlas of meiosis in autopolyploid Brassica rapa

Background

Polyploidy is considered as a basic event in plant speciation and evolution in nature, and the cytological and proteomic profilings of floral buds at meiosis (FAM) would definitely contribute to a better understanding of the polyploid-associated effects during plant reproduction cycle.

Results

Herein, the cytological investigations demonstrated that chromosome behaviors such as univalent and multivalent at prophase I, chaotic alignments at metaphase, aberrant segregation at telophase, were frequently observed during meiosis in autotetraploid Brassica rapa. The proteomic analysis showed a total of 562 differentially expressed proteins (DEPs) were identified in FAM between autotetraploid and diploid B. rapa. Notably, PARP2 and LIG1 related to base excision repair and BARD1 involved in recombination were significantly down-regulated in autotetraploid B. rapa, which indicated DNA repair pathway were more likely affected during meiosis in autotetraploid B. rapa. The functional analysis showed that DEPs assigned to “chromatin structure and dynamics”, “cell cycle control, cell division, chromosome partitioning” and “cytoskeleton” were preferentially up-regulated, which suggested a robust regulation of cell division in autotetraploid B. rapa. In combination with the floral RNA-seq data released, a number of DEPs were found positively correlated with their transcript abundance, but posttranslational modification of proteins might also play a role in regulating meiosis course after polyploidization.

Conclusions

In general, this study provides a detailed cytology and proteome landscape of FAM between diploid and autotetraploid B. rapa, which definitely affords us a better understanding of uniformity and discrepancy of meiosis at the plant reproductive stage before and after polyploidization.

Electronic supplementary material

The online version of this article (10.1186/s13578-019-0313-z) contains supplementary material, which is available to authorized users.

Morpho-physiological and proteomic responses of Aegilops tauschii to imposed moisture stress

Moisture stress is the most important limitation of wheat production in the worldwide. Among the tribe Triticeae, Aegilops tauschii is one of the most valuable gene sources of resistance to abiotic stresses. In order to identify the most tolerant accession to moisture stress, and to understand its adaptive mechanisms at the molecular level, the present experiment was carried out on ten Ae. tauschii accessions under normal (95% soil pot capacity) and moisture stress (45% soil pot capacity) conditions. At the start of the heading time, the expanded flag leaves of treated and untreated plants were sampled for two-dimensional electrophoresis (2-DE) based on proteomics approach. A19 accession was less affected by the imposed moisture stress; therefore, it was used for the proteomics experiment. Among 252 protein spots which were reproducibly detected in each given 2-DE gels, 25 spots showed significant differences between the two moisture treatments; 17 spots were upregulated and 8 spots were downregulated. The identified proteins by MALDI-TOF/TOF, were allocated to seven functional protein groups, which were mainly involved in photosynthesis/respiration (28.5%), carbohydrate metabolism (14.2%), energy metabolism (7.1%), chaperone (14.2%), protein translation and processing (14.2%), repair and stability of the genome (7.1%) and unknown function (14.2%). We report this for the first time that RMI2 protein (in the group of repair and stability of the genome) was significantly changed in wheat in response to moisture stress. We believe that, the identified proteins could play important roles in acclimation and tolerance to moisture stress and provide the genetic pathways for improving tolerance to moisture stress in wheat.