). † These authors contributed equally to this work. SUMMARYRNA-directed DNA methylation (RdDM) is an important epigenetic mechanism for silencing transgenes and endogenous repetitive sequences such as transposons. The RD29A promoter-driven LUCIFERASE transgene and its corresponding endogenous RD29A gene are hypermethylated and silenced in the Arabidopsis DNA demethylase mutant ros1. By screening for second-site suppressors of ros1, we identified the RDM12 locus. The rdm12 mutation releases the silencing of the RD29A-LUC transgene and the endogenous RD29A gene by reducing the promoter DNA methylation. The rdm12 mutation also reduces DNA methylation at endogenous RdDM target loci, including transposons and other repetitive sequences. In addition, the rdm12 mutation affects the levels of small interfering RNAs (siRNAs) from some of the RdDM target loci. RDM12 encodes a protein with XS and coiled-coil domains, and is similar to SGS3, which is a partner protein of RDR6 and can bind to double-stranded RNAs with a 5¢ overhang, and is required for several post-transcriptional gene silencing pathways. Our results show that RDM12 is a component of the RdDM pathway, and suggest that RdDM may involve double-stranded RNAs with a 5¢ overhang and the partnering between RDM12 and RDR2.

Salinity is an abiotic stress that substantially limits crop production worldwide. To identify salt stress tolerance determinants, we screened for Arabidopsis mutants that are hypersensitive to salt stress and designated these mutants as short root in salt medium (rsa). One of these mutants, rsa3-1, is hypersensitive to NaCl and LiCl but not to CsCl or to general osmotic stress. Reactive oxygen species (ROS) over-accumulate in rsa3-1 plants under salt stress. Gene expression profiling with Affymetrix microarray analysis revealed that RSA3 controls expression of many genes including genes encoding proteins for ROS detoxification under salt stress. Map-based cloning showed that RSA3 encodes a xyloglucan galactosyltransferase, which is allelic to a gene previously named MUR3/KAM1. The RSA3/MUR3/KAM1-encoded xylogluscan galactosyltransferase regulates actin microfilament organization (and thereby contributes to endomembrane distribution) and is also involved in cell wall biosynthesis. In rsa3-1, actin cannot assemble and form bundles as it does in the wild-type but instead aggregates in the cytoplasm. Furthermore, addition of phalloidin, which prevents actin depolymerization, can rescue salt hypersensitivity of rsa3-1. Together, these results suggest that RSA3/MUR3/KAM1 along with other cell wall-associated proteins plays a critical role in salt stress tolerance by maintaining the proper organization of actin microfilaments in order to minimize damage caused by excessive ROS.

Since Professor L.A. Zadeh published “Fuzzy Set Theory” in the 1960s, the theory of fuzzy mathematics has been formally established and developed and has been gradually introduced into work in all walks of life. At the same time, fuzzy mathematics theory has also been widely used in VR industry selection. In the stock strategy, the advantages of improving unit classification accuracy, screening high-quality stocks, and constructing near-perfect investment portfolios continue to emerge. On the other hand, with the increasing maturity and continuous development of China’s computer and Internet technologies, the VR industry has gained a new round of development space, and its own investment value and the investable space between related industries have been gradually tapped. Different from the analysis of quantitative stock selection by constructing a logistics multifactor stock selection model in the existing research, the research mainly adopts the random forest algorithm based on fuzzy mathematics to construct the initial investment strategy portfolio. Secondly, different from the single effective frontier algorithm, the research is based on the random forest algorithm, calculates the average AUC of the index, and continuously checks and tests the results to obtain the optimal investment portfolio. Finally, select appropriate risk indicators and performance indicators to evaluate the performance of the strategy portfolio. The study concludes that the portfolios selected by the random forest model are highly investable and have good stability.

ADP-ribosylation factors (ARFs) have been widely identified as being involved in regulation of cell differentiation, intracellular vesicle transport, and cytoskeleton organization in animals and plants. To systematically clarify the ARF gene family in rice, eight putative rice ARF genes (OsARFs) were detected by searching the rice genome database. The OsARFs can be classified into class I (OsARFA1a-OsARFA1e) and class II (OsARFB1a-OsARFB1c) by comparing their deduced amino acid sequences with other known ARFs. Most OsARFs are composed of six exons and five introns, though OsARFB1b has three exons and two introns. The OsARFs are usually expressed in various developing organs, whereas OsARFA1a is predominantly expressed in young roots and in caryopses at early development stages. The histochemical localization of OsARFs in various developing organs was confirmed in young leaves, the pericycle of young roots, and the aleurone layer of developing caryopses. Furthermore, the expression of OsARFA1a was confirmed specifically in the aleurone layer and immature embryos of developing caryopses. The present work provides a foundation for further clarifying the physiological functions of OsARFs in rice growth and development.