Three new Pyrenula species with 3-septate ascospores with red or orange oil when over-mature (Ascomycota, Pyrenulales, Pyrenulaceae) from China.

The lichenised fungal genus Pyrenula is a very common crustose lichen element in tropical to subtropical forests, but little research has been done on this genus in China. During our study on Pyrenula in China, based on morphological characteristics, chemical traits and molecular phylogenetic analysis (ITS and nuLSU), three new 3-septate species with red or orange oil in over-mature ascospores were found: Pyrenulainspersasp. nov., P.thailandicoidessp. nov. and P.apiculatasp. nov. Compared to the known 3-septate species of Pyrenula with red or orange oil, P.inspersa is characterised by the inspersed hamathecium; P.thailandicoides is characterised by the IKI+ red hamathecium and the existence of an unknown lichen substance; and P.apiculata is characterised by the absence of endospore layers in the spore tips and the absence of pseudocyphellae. It is reported for the first time that the presence of a gelatinous halo around the ascospores of Pyrenula is common. A word key for the Pyrenula species with red or orange oil in over-mature ascospores is provided.

Distribution and diversity of myxomycetes in Tiantangzhai National Forest Park, China.

Although myxomycetes are ubiquitous in terrestrial ecosystems, studies on their distribution and diversity in subtropical humid forests are still lacking. Field collections and moist chamber cultures were conducted from May to October within a two-year period in the Tiantangzhai National Forest Park of China. A total of 1,492 records representing 73 species belonging to 26 genera were obtained, of which 243 records/37 species were from field collections, and 1,249 records/52 species were from moist chamber cultures. Among the specimens obtained by culturing, 896 records/38 species and 353 records/37 species were obtained from living bark and ground litter, respectively. ANOVA showed that the sampling months had significant impacts on collection of myxomycetes from field and those that inhabit litter. An LEfSe analysis indicated that Arcyria was significantly abundant in August, while Stemonitis and Physarum were more abundant in July when collected from field. An RDA analysis showed that temperature was the main factor that affected the litter-inhabiting myxomycetes. The ANOVA indicated that forest type was the significant factor for bark-inhabiting myxomycetes. Diderma effusum was primarily obtained from mixed forests, while Clastoderma debaryanum and Colloderma oculatum were more common in coniferous forests. The RDA analysis indicated that the vegetation, pH, water retention, and elevation were the primary factors that affected the bark-inhabiting myxomycetes.

Nitric oxide regulates perylenequinones biosynthesis in Shiraia bambusicola S4201 induced by hydrogen peroxide.

Shiraia bambusicola has been used as a traditional Chinese medicine for a long history. Its major medicinal active metabolites are perylenequinones, including hypocrellin A, elsinochrome A and so on. At present, the fermentation yield of perylenequinones is low, and its complex biosynthesis and regulatory pathways are still unclear. In this study, nitric oxide, as a downstream signal molecule of hydrogen peroxide, regulates the biosynthesis of perylenequinones. Exogenous addition of 0.01 mM sodium nitroprusside (nitric oxide donor) can promote perylenequinones production by 156% compared with the control. Further research found that hydrogen peroxide and nitric oxide increased the transcriptional level of the biosynthetic genes of hypocrellin A. The results showed that nitric oxide is involved in the biosynthesis and regulation of perylenequinones in Shiraia bambusicola as a signal molecule. In the future, the yield of perylenequinones can be increased by adding exogenous nitric oxide in fermentation.

New species and records of Chapsa (Graphidaceae) in China.

We studied the genus Chapsa in China based on morphological characteristics, chemical traits and molecular phylogenetic analysis. One species new to science (C.murioelongata M.Z. Dou & M. Li) and two records new to China were found (C.wolseleyana Weerakoon, Lumbsch & Lücking and C.niveocarpa Mangold). Chapsamurioelongata sp. nov. is characterised by its lobed thalline margin, orange discs with white pruina, clear hymenium, and submuriform and long ascospores. Chapsawolseleyana was recombined into Astrochapsa based on phenotypic traits. Sequences of this species are for the first time reported here and phylogenetic analyses of three loci (mtSSU, ITS and nuLSU) supported the position of this species within Chapsa. A key for the Chapsa species known in China is provided.

Identification of ZHOUPI Orthologs in Rice Involved in Endosperm Development and Cuticle Formation.

The endosperm occupies most of the available space within mature rice seeds, contains abundant nutrients, and directly influences both the quality and quantity of rice production. Initial reports noted that AtZHOUPI (AtZOU) coordinates endosperm breakdown and the concomitant separation of the embryo from this structure in Arabidopsis. The results of this study show that rice genomes contain two most closely related homologs of AtZOU, OsZOU-1 and OsZOU-2; of these, OsZOU-1 expression is limited to within the endosperm where it can be detected throughout this structure 5 days after pollination (DAP). Its expression gradually decreases from seven DAP to nine DAP. The second of the two most closely related homologs, OsZOU-2, is highly expressed in leaves and stem, but is not detected in developing seeds. Heterologous expression of OsZOU-1 and OsZOU-2 in Atzou-4 mutants also revealed that OsZOU-1 partially complements the seed phenotypes of these individuals, while its counterpart, OsZOU-2, was unable to recover these phenotypes. The over-expression of OsZOU-1 severely disrupts both seed development and plant growth in transgenic rice lines, as plants in which this gene has been knocked down failed in the separation of endosperm from embryo and cuticle formation during seed development. The results of this study therefore suggest that OsZOU-1 is orthologous to the AtZOU, and regulates both endosperm development and cuticle formation in rice.

Overexpression of AmRosea1 Gene Confers Drought and Salt Tolerance in Rice.

Ectopic expression of the MYB transcription factor of AmROSEA1 from Antirrhinum majus has been reported to change anthocyanin and other metabolites in several species. In this study, we found that overexpression of AmRosea1 significantly improved the tolerance of transgenic rice to drought and salinity stresses. Transcriptome analysis revealed that a considerable number of stress-related genes were affected by exogenous AmRosea1 during both drought and salinity stress treatments. These affected genes are involved in stress signal transduction, the hormone signal pathway, ion homeostasis and the enzymes that remove peroxides. This work suggests that the AmRosea1 gene is a potential candidate for genetic engineering of crops.

The Indeterminate Domain Protein ROC1 Regulates Chilling Tolerance via Activation of DREB1B/CBF1 in Rice.

Abiotic stress, including salinity, drought and cold, severely affect diverse aspects of plant development and production. Rice is an important crop that does not acclimate to cold; therefore, it is relatively sensitive to low temperature stress. Dehydration-responsive element-binding protein 1s (DREB1s)/C-repeat binding factors (CBFs) are well known for their function in cold tolerance, but the transcriptional regulation of CBFs remains elusive, especially in rice. Here, we performed a yeast one-hybrid assay using the promoter of CBF1, a cold-induced gene, to isolate transcriptional regulators of CBF1. Among the seven candidates identified, an indeterminate domain (IDD) protein named ROC1 (a regulator of CBF1) was further analyzed. The ROC1 transcript was induced by exogenously-treated auxin, while it was not altered by cold or ABA stimuli. ROC1-GFP was localized at the nucleus, and ROC1 showed trans-activation activity in yeast. The electrophoretic mobility shift assay (EMSA) and ChIP analyses revealed that ROC1 directly bound to the promoter of CBF1. Furthermore, ROC1 mutants exhibited chilling-sensitive symptoms and inhibited cold-mediated induction of CBF1 and CBF3, indicating that ROC1 is a positive regulator of cold stress responses. Taken together, this study identified the CBF1 regulator, and the results are important for rice plant adaptation to chilling stress.