Evidence of the predominance of passive symplastic phloem loading and sugar transport with leaf ageing in Camellia oleifera

Phloem loading and transport of sugar from leaves to sink tissues such as fruits are crucial for yield formation.Camellia oleifera is an evergreen horticultural crop with high value;however,its low production limits the development of the C.oleifera industry.In this study,using a combination of ultrastructural observation,fluorescence loss in photobleaching(FLIP)and inhibitor treatment,we revealed that C.oleifera leaves mainly adopt a symplastic loading route from mesophyll cells to the surrounding vascular bundle cells in minor veins.HPLC assays showed that sucrose is the main sugar transported and only a small amount of raffinose or stachyose was detected in petioles,supporting a passive symplastic loading route in C.oleifera leaves.Compared to leaves grown this year(LT),the carbohydrate synthesis capacity in leaves grown last year(LL)was decreased while LL retained more soluble sugar,suggesting a decrease in transport capacity with leaf ageing.TEM and tissue staining showed that a reduction in plasmodesmata density leads to a decline in the degree of cellular coupling and is responsible for the weakening transport capacity in older leaves.RNA-seq revealed several differentially expressed genes(DEGs)including CoPDCB1-1,CoSUT1 and CoSWEET12,which are likely involved in the regulation of phloem loading and sugar transport.An expression correlation network is constructed between PD-callose binding protein genes,sugar transporter genes and senescence-associated genes.Collectively,this study provides the evidence of the passive symplastic phloem loading pathway in C.oleifera leaves and constructs the correlation between sugar transport and leaf ageing.

Impact of Different Rates of Nitrogen Supplementation on Soil PhysicochemicalProperties and Microbial Diversity in Goji Berry

Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyze the functions of differential nitrogen application rates including low(N1),medium(N2),and high(N3)levels in soil microbial community structure(bacterial and fungal)at 2 diverse soil depths(0-20,20-40 cm)through high-throughput sequencing technology by targeting 16S RNA gene and ITS1&ITS2 regions.All the observed physicochemical parameters exhibited significant improvement(p<0.05)with increased levels of nitrogen and the highest values for most parameters were observed at N2.However,pH decreased(p<0.05)gradually.The alpha and beta diversity analyses for bacterial and fungal communities’metagenome displayed more similarities than differences among all groups.The top bacterial and fungal phyla and genera suggested no obvious(p>0.05)differences among three group treatments(N1,N2,and N3).Furthermore,the functional enrichment analysis demonstrated significant(p<0.05)enrichment of quorum sensing,cysteine and methionine metabolism,and transcriptional machinery for bacterial communities,while various saprotrophic functional roles for fungal communities.Conclusively,moderately reducing the use of N-supplemented fertilizers is conducive to increasing soil nitrogen utilization rate,which can contribute to sustainable agriculture practices through improved soil quality,and microbial community structure and functions.

Ground-Based Atmospheric CO_(2),CH_(4),and CO Column Measurements at Golmud in the Qinghai-Tibetan Plateau and Comparisons with TROPOMI/S5P Satellite Observations

Measurements of carbon dioxide(CO_(2)),methane(CH_(4)),and carbon monoxide(CO)are of great importance in the Qinghai-Tibetan region,as it is the highest and largest plateau in the world affecting global weather and climate systems.In this study,for the first time,we present CO_(2),CH_(4),and CO column measurements carried out by a Bruker EM27/SUN Fourier-transform infrared spectrometer(FTIR)at Golmud(36.42°E,94.91°N,2808 m)in August 2021.The mean and standard deviation of the column-average dry-air mixing ratio of CO_(2),CH_(4),and CO(XCO_(2),XCH_(4),and XCO)are 409.3±0.4 ppm,1905.5±19.4 ppb,and 103.1±7.7 ppb,respectively.The differences between the FTIR co-located TROPOMI/S5P satellite measurements at Golmud are 0.68±0.64%(13.1±12.2 ppb)for XCH_(4) and 9.81±3.48%(–10.7±3.8 ppb)for XCO,which are within their retrieval uncertainties.High correlations for both XCH_(4) and XCO are observed between the FTIR and S5P satellite measurements.Using the FLEXPART model and satellite measurements,we find that enhanced CH_(4) and CO columns in Golmud are affected by anthropogenic emissions transported from North India.This study provides an insight into the variations of the CO_(2),CH_(4),and CO columns in the Qinghai-Tibetan Plateau.

Advances and challenges of cellulose functional materials in sensors

As the most abundant natural polymer material on the earth,cellulose is a promising sustainable sensing material due to its high mechanical strength,excellent biocompatibility,good degrada-tion,and regeneration ability.Considering the inherent advantages of cellulose and the success of modern sensors,applying cellulose to sensors has always been the subject of considerable investigation,and significant progress has been made in recent decades.Herein,we reviewed the research progress of cellulose functional materials(CFMs)in recent years.According to the different sources of cellulose,the classification and preparation methods for the design and func-tionalization of cellulose were summarized with the emphasis on the relationship between their structure and properties.Besides,the applications of advanced sensors based on CFMs in recent years were also discussed.Finally,the potential challenges and prospects of the development of sensor based on CFMs were outlined.

Identification and functional characterization of an odorant receptor in pea aphid,Acyrthosiphon pisum

The sensitive olfactory system is necessary for survival of insects.Odorant receptors (ORs)are located on the dendrites of olfactory receptor neurons and play a critical role in odor detection.Insect ORs are functionally analyzed via heterologous expression in a Xenopus oocyte system using a two-electrode voltage-clamp (TEVC)electrophysiological recording.Here,we have identified a novel OR in the pea aphid,Acyrthosiphon pisum,then we cloned and named it ApisOR4.We analyzed the ApisOR4 tissue expression patterns and found expression only in antennae tissues.Further functional analysis using TEVC revealed that ApisOR4 is broadly tuned to eight volatiles,which elicit electrophysiological response in pea aphid antennae.This study provides an initial functional analysis of aphid ORs and identifies candidate volatiles to be used in developing new strategies for aphid control.

Synergistic effects of plant hormones on spontaneous late-ripening mutant of'Jinghong'peach detected by transcriptome analysis

Objectives:Peach(Prunus persica L.)is an ancient fruit tree that originated from China.It is the climacteric fruit belonging to genus Prunus in family Rosaceae.Ethylene,which is produced during ripening,accelerates fruit softening,and therefore peaches cannot be stored for a long time.Materials and Methods:To study the mechanism of fruit late ripening,transcriptome analysis of the fruit of a late-ripening mutant of'Jinghong'peach was performed to identify genes and pathways involved in fruit late ripening.Results:A total of 1805,1511,and 2309 genes were found to be differentially expressed in W2_vs_M1,W3_vs_M2,and W3_vs_M3,respectively.Functional enrichment analysis of the differentially expressed genes showed they were related to carotenoid biosynthesis,starch and sucrose metabolism plant hormone signal transduction,flavonoid biosynthesis,and photosynthesis.The expression trends of ripening-related genes that encode transcription factors and plant hormone signal transduction-related genes that encode enzymes were similar.Conclusions:It will help to elucidate the transcriptional regulatory network of fruit development in the spontaneous late-ripening mutant of‘Jinghong’peach and provide a theoretical basis for understanding the molecular regulatory mechanism of fruit ripening.