Detection and Evaluation of Metals in Tea and Soils of Tea Gardens in Mingshan

[ Objective] The study aimed to detect and assess metal ions in tea and soil of tea gardens in Mingshan County. [ Method] Seven metals （ including Pb, Cr, Cu, Ca, Mn, Mg and Zn） in soil and tea samples of tea gardens in Mingshan were determined by atomic absorption spectrometry, and the pollution situation of the soil and tea by Pb, Cr and Cu were evaluated using the single factor pollution index and Nemerow pollu- tion index, finally the accumulation of heavy metals in different soils were analyzed by the enrichment factor. I-Result] There was little difference for the same heavy metals in various soils, but different heavy metals had very significant difference. The enrichment factors of metals needed by tea growing, such as Ca, Mn, Mg and Zn, were higher than heavy metals like Pb and Cr. In addition, soils and tea of the six tea gardens were not polluted by Pb, Cr and Cu, and both single factor pollution index and Nemerow pollution index were below 0.7. [ Condusion] The research could provide scientific references for preventing tea from being polluted by heavy metals.

Identification and functional analysis of miRNAs in developing kernels of a viviparous mutant in maize

Given the important roles of miRNAs in post-transcriptional gene regulation, identification of differentially expressed miRNAs will facilitate the elucidation of molecular mechanisms underlying kernel development. In this study, we constructed a small RNA library to comprehensively represent the full complement of individual small RNAs and to characterize miRNA expression profiles in pooled ears of maize(Zea mays L.) at 10, 15,20, 22, 25 and 30 days after pollination(DAP). At least 21 miRNAs were differentially expressed. The differential expression of three of these miRNAs, i.e., miR528a, miR167a and miR160b, at each stage was verified by qRT-PCR. The results indicated that these miRNAs might be involved in kernel development. In addition, the predicted functions of target genes indicated that most of the target genes are involved in signal transduction and cell communication pathways, particularly the auxin signaling pathway. The expression of candidate germination-associated miRNAs was analyzed by hybridization to a maize genome microarray, and revealed differential expression of genes involved in plant hormone signaling pathways. This finding suggests that phytohormones play a critical role in the development of maize kernels. We found that in combination with other miRNAs, miR528a regulated a putative laccase, a Ring-H2 zinc finger protein and a MADS box-like protein, whereas miR167a and miR160b regulated multiple target genes,including ARF(auxin response factor), a member of the B3 transcription factor family. All three miRNAs are important for ear germination, development and physiology. The small RNA transcriptomes and mRNA obtained in this study will help us gain a betterunderstanding of the expression and function of small RNAs in the development of maize kernel.

Cloning and Expression of the Serine Carboxypeptidase Gene in Zea mays and Its Antifungal Activity against Rhizoctonia solani

The authors cloned and identified a new maize serine carboxypeptidase gene named ZmSCP from R15 inbred lines seedlings which were induced by Rhizoctonia solani AGI-IA. ZmSCP encodes a 332 amino acid protein with a predicted molecular mass of 36.5 kDa and pI of 4.75. Phylogenetic analysis revealed that ZmSCP showed closer kinship with Oryza sativa and sorghum, which belong to the same evolutionary branch. Amino acid sequence analysis revealed that there are four types of amino acids in ZmSCP, the percentages of them are 43.1%, 26.9%, 13.9% and 13.1%. The authors subsequently purified the recombinant protein which expressed in Escherichia coli BL21 and analyzed its antimicrobial activities in vitro. Results showed that the recombinant protein inhibited hyphal growth of Rhizoctonia solani. The study suggests that the expression of ZmSCP is closely related to maize sheath blight resistance caused by Rhizoctonia solani. Further, the antifungal activity showed that ZmSCP may play at role in the disease resistance response.

Genome of the Giant Panda Roundworm Illuminates Its Host Shift and Parasitic Adaptation

Baylisascaris schroederi,a roundworm(ascaridoid)parasite specific to the bamboofeeding giant panda(Ailuropoda melanoleuca),represents a leading cause of mortality in wild giant panda populations.Here,we present a 293-megabase chromosome-level genome assembly of B.schroederi to infer its biology,including host adaptations.Comparative genomics revealed an evolutionary trajectory accompanied by host-shift events in ascaridoid parasite lineages after host separations,suggesting their potential for transmission and rapid adaptation to new hosts.Genomic and anatomical lines of evidence,including expansion and positive selection of genes related to the cuticle and basal metabolisms,indicate that B.schroederi undergoes specific adaptations to survive in the sharp-edged bamboo-enriched gut of giant pandas by structurally increasing its cuticle thickness and efficiently utilizing host nutrients through gut parasitism.Additionally,we characterized the secretome of B.schroederi and predicted potential drug and vaccine targets for new control strategies.Overall,this genome resource provides new insights into the host adaptation of B.schroederi to the giant panda as well as the host-shift events in ascaridoid parasite lineages.Our findings on the unique biology of B.schroederi will also aid in the development of prevention and treatment measures to protect giant panda populations from roundworm parasitism.

OsMADS32 interacts with PI-like proteins and regulates rice flower development

OsMADS32 is a monocot specific MIKCc type MADS‐box gene that plays an important role in regulating rice floral meristem and organs identity, a crucial process for reproductive success and rice yield. However, its underlying mechanism of action remains to be clarified. Here, we characterized a hypomorphic mutant allele of OsMADS32/CFO1, cfo1‐3 and identified its function in controlling rice flower development by bioinformatics and protein‐protein interaction analysis. The cfo1‐3 mutant produces defective flowers, including loss of lodicule identity, formation of ectopic lodicule or hull‐like organs and decreased stamen number, mimicking phenotypes related to the mutation of B class genes. Molecular characterization indicated that mis‐splicing of OsMADS32 transcripts in the cfo1‐3 mutant resulted in an extra eight amino acids in the K‐domain of OsMADS32 protein. By yeast two hybrid and bimolecular fluorescence comple-mentation assays, we revealed that the insertion of eight amino acids or deletion of the internal region in the K1 subdomain of OsMADS32 affects the interaction between OsMADS32 with PISTILLATA （PI）‐like proteins OsMADS2 and OsMADS4. This work provides new insight into the mecha-nism by which OsMADS32 regulates rice lodicule and stamen identity, by interaction with two PI‐like proteins via its K domain.

Alleviative effect of quercetin on germ cells intoxicated by 3-methyl-4-nitrophenol from diesel exhaust particles

As a component of diesel exhaust particles, 3-methyl-4-nitrophenol （4-nitro-m-cresol, PNMC） is also a metabolite of the insecticide fenitrothion and imposes hazardous effects on human health. In the present study, the alleviative effect of a common antioxidant flavonoid quercetin on mouse germ cells intoxicated by PNMC was inves- tigated. Results showed that a single intraperitoneal injection of PNMC at 100 mg/kg induced severe testicular damage after one week. PNMC-treated mice showed a significant loss of germ cells （approximate 40% loss of round germ cells）. PNMC caused an increase of hydroxyl radical and hydrogen peroxide production and lipid peroxidation, as well as a decrease in glutathione level, superoxide dismutase and glutathione peroxidase activities. Furthermore, treatment of PNMC increased expression of the pro-apoptotic protein Bax and decreased expression of the anti-apoptotic protein BcI-XL in germ cells. In addition, testicular caspase-3 activity was significantly up-regulated and germ cell apoptosis was significantly increased in the PNMC-treated mice. In contrast, combined administration of quercetin at 75 mg/kg significantly attenuated PNMC-induced testicular toxicity. These results indicate that the antioxidant quercetin displays a remarkable protective effect on PNMC-induced oxidative damage in mouse testes and may represent an efficient supplement to attenuate reproductive toxicity by environmental toxicants to ensure healthy sperm production.