Two polypores from Yunnan new to China

1 INTRODUCTION Wood-rotting fungi have been intensively studied in China （Dai ＆ Niemela 2002; Dai et al. 2003, 2004a, 2004b; Dai ＆ Penttil/i 2006）, and some new species and new records were found from tropical and subtropical forests in southern part of the Country （Cui et al. 2006b; Cui et al. 2007; Dai 2004; Dai ＆ Cui 2005; Dai ＆ Yuan 2005; Yuan et al. 2004）. Some species are new forest pathogens （Cui et al. 2006a; Dai et al. 2001, 2002, 2004）.     

Resolving the Activation Site of PositiveRegulators in Plant PhosphoenolpyruvateCarboxylase

Dear Editor, Phosphoenolpyruvate carboxylase （PEPC; EC 4.1.1.31） islocated at an important branch point in the carbohydratemetabolism of plants. The enzyme is a homotetramer andcatalyzes the addition of bicarbonate to phosphoenolpyru-vate （PEP） to form oxaloacetate and phosphate. PEPC isregulated by metabolites and phosphorylation. AIIostericfeedback inhibition is mainly regulated by L-malate andL-aspartate which bind to a site separated from the activecenter （Kai et al., 1999; Paulus et al., 2013）. Structure analy-sis of PEPC from Escherichia coli （Kai et al., 1999; Matsumuraet al., 2002）, Zea rnays （Matsumura et al., 2002）, Flaveria trin-ervia, and F. pringlei （Paulus et al., 2013） revealed that thesubstrate PEP and the feedback inhibitors bind to separatesites within each monomer.     

A Brassinosteroid-Signaling Kinase Interacts withMultiple Receptor-Like Kinases in Arabidopsis

Dear Editor, Higher plants have evolved hundreds of genes encodingreceptor-like kinases （RLKs）, which function as cell surfacereceptors perceiving developmental and environmental sig-nals （Shiu et al., 2004）. Many RLKs have been shown to playspecific roles in hormone responses, developmental regula-tion, defense against pathogen infection, and adaptationto abiotic stresses （Chae et al., 2009; Antolin-Llovera et al.,2012）. The mechanisms that ensure specific signal transduc-tion from each RLK to target cellular responses remain poorlyunderstood. Recent studies revealed that many RLKs trans-duce signals by phosphorylating receptor-like cytoplasmickinases （RLCKs）, which lack the transmembrane domainsbut are anchored at the plasma membrane through lipidmodification （Tang et al., 2008; Zhang et al., 2010; Shi et al.,2013）. There are over 400 RLKs and only about 150 RLCKs inArabidopsis （Shiu et al., 2004）. One outstanding question iswhether each RLCK mediates signaling downstream of a spe-cific RLK, participates in multiple RLK pathways, or mediatescrosstalk between RLK pathways.     

Efficient Gene Targeting in Zebrafish Mediated by a Zebrafish-Codon-Optimized Cas9 and Evaluation of Off-Targeting Effect

Targeted genome modifications with the Cas9/gRNA system derived from the clustered regularly interspaced short palin- dromic repeat/CRISPR-associated （CRISPR/Cas） system have been successfully used in cultured human cells as well as in most model organisms, including zebrafish （Danio rerio）, mouse, and fruit fly （Chang et al., 2013; Cong et al., 2013; Gratz et al., 2013; Hwang et al., 2013; Jao et al., 2013; Shen et al., 2013; Wei et al., 2013）. Its application in zebrafish is particu- larly attractive due to the ease of handling this organism and the simple application of this method by direct injection of Cas9/ gRNA. However, the information about its specificity in this organism is very limited and needs further evaluation. In addition, it is conceivable that a Cas9 mRNA optimized for zebrafish codon preference could enhance its activity.     

Two species in Hymenochaetaceae （Basidiomycota） new to China

1 INTRODUCTION Wood-inhabiting fungi from northern China were investigated extensively during last ten years, and the species in the area are relatively well known （Dai 2000; Dai et al. 2006, 2007; Wei et al. 2005; Yuan et al. 2006）. However, they are scantily reported in tropical forests of China （Dai et al. 2001, 2002, 2004）. By the support of the Ministry of Science and Technology of China, two field investigations were made in Jianfengling and Bawangling Nature Reserve of Hainan Province in 2006.     

To Grow or Not to Grow： FERONIA Has Her Say

Plant cells differ from their animal counterparts such that they are encased in a complex wall structure, crucial for cell growth through a dynamic equilibrium of rigidity and flexibility. Cell wall extensibility can be greatly influenced by apoplastic pH and reactive oxygen species （ROS） （Duan et al., 2014; Haruta et al., 2014）. Several recent works demonstrated that the receptor-like kinase （RLK） FERONIA （FER） is critical to fine-tune cell growth in a spatiotemporal and context-dependent manner by controlling apoplastic pH （Haruta et al., 2014） and ROS （Duan et al., 2010, 2014）, likely balancing wall rigidity for cell integrity and flexibility for cell expansion.     

PhGRL2 Protein,Interacting with PhACO1, Is Involved in Flower Senescence in the Petunia

Dear Editor, The pathways of ethylene biosynthesis and signaling have been studied in detail （Ji and Guo, 2013）. Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 （RTE1）, interacting with ETR1, and its homologs tomato GREEN RIPE （SlGR） and SlGRL1, and rice OsRTH1 negatively regulate the ethylene signaling （Barry and Giovannoni, 2006, Resnick et al., 2006; Dong et al., 2010; Zhang et al., 2012）. A newly published study suggested that a cytochrome b5 and RTE1 are functional partners in promoting ETRl-mediated repression of ethylene signaling in Arabidopsis （Chang et al., 2014）. However, AtRTH, RTE1 homolog in Arabidopsis, and its closest homolog in the tomato, SlGRL2 （GR-like2）, do not play a role in ethylene signaling （Dong et al., 2010）, and the function of the homologs of these members is not well known.     

Genome-Wide Prediction of Highly Specific Guide RNA Spacers for CRISPR-Cas9-Mediated Genome Editing in Model Plants and Major Crops

Dear Editor,
RNA-guided genome editing （RGE） using the Streptococcus pyogenes CRISPR-Cas9 system （Jinek et al., 2012; Cong et al., 2013; Mall et al., 2013b） is emerging as a simple and highly efficient tool for genome editing in many organisms. The Cas9 nuclease can be programmed by dual or single guide RNA （gRNA） to cut target DNA at specific sites,     

MYPT1 Sustains Centromeric Cohesion and the Spindle-Assembly Checkpoint

During mitosis, cohesins hold the sister chromatids together until anaphase when arm cohesins are removed （Peters et al., 2008; Yao and Dai, 2012）. The shugoshin （Sgo） proteins play pivotal roles during this stage. There is only one shu- goshin in the fly and budding yeasts, while there are two in other organisms （including fission yeasts）. The two mamma- lian shugoshins, Sgol and Sgo2, carry out distinct functions： Sgol mainly in mitosis, and Sgo2 mainly in meiosis and perturbed mitosis. Mitotic cyclin-dependent kinase 1 （CDKI） phosphorylates Sgol, and targets the Sgol-protein phospha- tase 2A （PP2A） complex to protect centromeric cohesin （Kitajima et al., 2006; Tang et al., 2006; Liu et al., 2012）,