Oil-tea tree (Camellia oleifera) is the most important edible oil tree species in China with late-acting self-incompatibility (LSI) properties. The mechanism of LSI is uncertain, which seriously hinders the research on its genetic characteristics, construction of genetic map, selection of cross breeding parents and cultivar arrangement. To gain insights into the LSI mechanism, we performed cytological, transcriptomic, proteomic and metabolomic studies on self- and cross-pollinated pistils. The studies identified 166,591 transcripts, 6851 proteins and 6455 metabolites. Transcriptomic analysis revealed 1197 differentially expressed transcripts between self- and cross-pollinated pistils and 47 programmed cell death (PCD)-control transcripts. Trend analysis by Pearson correlation categorized nine trend graphs linked to 226 differentially expressed proteins and 38 differentially expressed metabolites. Functional enrichment analysis revealed that the LSI was closely associated with PCD-related genes, mitogen-activated protein kinase (MAPK) signaling pathway, plant hormone signal transduction, ATP-binding cassette (ABC) transporters and ubiquitin-mediated proteolysis. These particular trends in transcripts, proteins and metabolites suggested the involvement of PCD in LSI. The results provide a solid genetic foundation for elucidating the regulatory network of PCD-mediated self-incompatibility in C. oleifera.
Generalized quasi-topological gravities (GQTGs) are higher-curvature extensions of Einstein gravity in D-dimensions. Their defining properties include possessing second-order linearized equations of motion around maximally symmetric backgrounds as well as non-hairy generalizations of Schwarzschild’s black hole characterized by a single function, f(r) ≡ −gtt
= grr
-1, which satisfies a second-order differential equation. In arXiv:1909.07983 GQTGs were shown to exist at all orders in curvature and for general D. In this paper we prove that, in fact, n − 1 inequivalent classes of order-n GQTGs exist for D ≥ 5. Amongst these, we show that one —and only one— type of densities is of the Quasi-topological kind, namely, such that the equation for f(r) is algebraic. Our arguments do not work for D = 4, in which case there seems to be a single unique GQT density at each order which is not of the Quasi-topological kind. We compute the thermodynamic charges of the most general D-dimensional order-n GQTG, verify that they satisfy the first law and provide evidence that they can be entirely written in terms of the embedding function which determines the maximally symmetric vacua of the theory.
Salicylic acid (SA) is a plant hormone involved in a series of growth, development, and stress responses in plants. Nonexpressor of pathogenesis‐related genes 1 (NPR1) is the core regulatory gene in the process of SA‐mediated systemic acquired resistance (SAR). Whether NPR1 is involved in pollen tube growth mediated by SA and its derivative MeSA (methyl salicylate) remains to be explored. Here, we found that the contents of endogenous SA and MeSA in self‐ or cross‐pollinated pistils changed significantly, and exogenous SA and MeSA significantly promoted pollen germination and pollen tube elongation of Camellia oleifera at lower concentrations. CoNPR1, CoNPR3.1, CoNPR3.2, and CoNPR5 were identified, and they were all located in the nucleus. A high level of consistency was observed across the phylogenetic relationships, gene structures, and functional domains, indicating a clear division of function, as observed in other species. The expression levels of CoNPR1, CoNPR3.1, CoNPR3.2, and CoNPR5 in self‐ and cross‐pollinated pistils had certain regularity. Furthermore, they exhibited tissue‐specific expression pattern. CoNPR1 and CoNPR3.1 were expressed in pollen tubes, whose expression was regulated by SA or MeSA, and their expression patterns were basically consistent with the trend of pollen germination. These results indicate that SA and MeSA are involved in the pollen tube growth of C. oleifera, and CoNPRs may play an important role therein.
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