Influence of rice black streaked dwarf virus on the ecological fitness of non-vector planthopper Nilaparvata lugens （Hemiptera： Delphacidae）

Rice black streak dwarf virus （RBSDV） is transmitted by the small brown planthopper （SBPH）, Laodelphax striatellus （Fallen）. Non-vector rice brown planthopper （BPH）, Nilaparvata lugens （Stal）, shares the same host rice plants with SBPH in paddy fields. The changes in nutritional composition of rice plants infected by RBSDV and the ecological fitness of BPH feeding on the infected plants were studied under both artificial climate chamber and field conditions. Contents of 16 detected amino acids and soluble sugar in RBSDV infected rice plants were higher than those in the healthy ones. On the diseased plants BPH had significantly higher nymphal survival rates, nymphal duration of the males, weight of the female adults, as well as egg hatchability compared to BPH being fed on healthy plants. However, there was no obvious difference in female nymph duration, longevity and fecundity. Defense enzymes （superoxidase dismutase, SOD and catalase, CAT） and detoxifying enzymes （carboxylesterase, CAE and glutathione S-transferase, GST） in BPH adults fed on diseased plants had markedly higher activities. The results indicate rice plants infected by RBSDV improved the ecological fitness of the brown planthopper, a serious pest but not a transmitter of the RBSDV virus.

Mechanisms for flowering plants to benefit arthropod natural enemies of insect pests： Prospects for enhanced use in agriculture

Reduction of noncrop habitats, intensive use of pesticides and high levels of disturbance associated with intensive crop production simplify the farming landscape and bring about a sharp decline of biodiversity. This, in turn, weakens the biological control ecosystem service provided by arthropod natural enemies. Strategic use of flowering plants to enhance plant biodiversity in a well-targeted manner can provide natural enemies with food sources and shelter to improve biological control and reduce dependence on chemical pesticides. This article reviews the nutritional value of various types of plant-derived food for natural enemies, possible adverse effects on pest management, and the practical application of flowering plants in orchards, vegetables and field crops, agricultural systems where most research has taken place. Prospects for more effective use of flowering plants to maximize biological control of insect pests in agroecosystem are good but depend up on selection of optimal plant species based on information on the ecological mechanisms by which natural enemies are selectively favored over pest species.

Male nutritional status does not impact the reproductive potential of female Cnaphalocrocis medinalis moths under conditions of nutrient shortage

In addition to sperm,some accessory substances transferred to females during copulation act as nuptial gifts by passing on valuable nutrients in many insect species.The nutritional status of the males can thus have a great effect on the mating behavior,fecundity and even the longevity of females.However,little is known about the effect of male nutritional status on the female reproductive traits in migratory insect species,particularly when females experience nutrient shortage and have to choose between reproduction and migration.Here,Cnaphalocrocis medinalis,a migratory rice pest in Asia,was studied to explore this issue.Our results showed that in male moths fed with honey solution,their gonads had higher energy content than gonads of starved males,resulting in increased energy content of the bursa copulatrix of females after mating with fed males.Such females showed increased mating frequency,fecundity and longevity compared to females mating with starved males,indicating that male moths deliver nuptial gifts to females and improve their reproductive performance.However,when females were starved,only about 45%mated,with just a single copulation,regardless of male nutritional status.Starved females showed lower fecundity,and a longer pre-oviposition period(indicating a greater propensity to migrate),compared to fed females.However,copulation still significantly extended their longevity.These results suggest that starved females invest in migration to escape deteriorating habitats,rather than investing the nuptial gift to increased fecundity.Our results further our understanding of the reproductive adaptability of migratory insects under conditions of food stress.

Biallelic mutations in spermatogenesis and centriole-associated 1 like(SPATC1L)cause acephalic spermatozoa syndrome and male infertility

Acephalic spermatozoa syndrome is a rare type of teratozoospermia that severely impairs the reproductive ability of male patients,and genetic defects have been recognized as the main cause of acephalic spermatozoa syndrome.Spermatogenesis and centrioleassociated 1 like(SPATC1L)is indispensable for maintaining the integrity of sperm head-to-tail connections in mice,but its roles in human sperm and early embryonic development remain largely unknown.Herein,we conducted whole-exome sequencing(WES)of 22 infertile men with acephalic spermatozoa syndrome.An in silico analysis of the candidate variants was conducted,and WES data analysis was performed using another cohort consisting of 34 patients with acephalic spermatozoa syndrome and 25 control subjects with proven fertility.We identified biallelic mutations in SPATC1L(c.910C>T:p.Arg304Cys and c.994G>T:p.Glu332X)from a patient whose sperm displayed complete acephalia.Both SPATC1L variants are rare and deleterious.SPATC1L is mainly expressed at the head–tail junction of elongating spermatids.Plasmids containing pathogenic variants decreased the level of SPATC1L in vitro.Moreover,none of the patient’s four attempts at intracytoplasmic sperm injection(ICSI)resulted in a transplantable embryo,which suggests that SPATC1L defects might affect early embryonic development.In conclusion,this study provides the first identification of SPATC1L as a novel gene for human acephalic spermatozoa syndrome.Furthermore,WES might be applied for patients with acephalic spermatozoa syndrome who exhibit reiterative ICSI failures.

The role of tyrosine phosphatase Shp2 in spermatogonial differentiation and spermatocyte meiosis

The transition from spermatogonia to spermatocytes and the initiation of meiosis are key steps in spermatogenesis and are precisely regulated by a plethora of proteins.However,the underlying molecular mechanism remains largely unknown.Here,we report that Src homology domain tyrosine phosphatase 2(Shp2;encoded by the protein tyrosine phosphatase,nonreceptor type 11[Ptpn11]gene)is abundant in spermatogonia but markedly decreases in meiotic spermatocytes.Conditional knockout of Shp2 in spermatogonia in mice using stimulated by retinoic acid gene 8(Stra8)-cre enhanced spermatogonial differentiation and disturbed the meiotic process.Depletion of Shp2 in spermatogonia caused many meiotic spermatocytes to die;moreover,the surviving spermatocytes reached the leptotene stage early at postnatal day 9(PN9)and the pachytene stage at PN11-13.In preleptotene spermatocytes,Shp2 deletion disrupted the expression of meiotic genes,such as disrupted meiotic cDNA 1(Dmc1),DNA repair recombinase rad51(Rad51),and structural maintenance of chromosome 3(Smc3),and these deficiencies interrupted spermatocyte meiosis.In GC-1 cells cultured in vitro,Shp2 knockdown suppressed the retinoic acid(RA)-induced phosphorylation of extracellular-regulated protein kinase(Erk)and protein kinase B(Akt/PKB)and the expression of target genes such as synaptonemal complex protein 3(Sycp3)and Dmc1.Together,these data suggest that Shp2 plays a crucial role in spermatogenesis by governing the transition from spermatogonia to spermatocytes and by mediating meiotic progression through regulating gene transcription,thus providing a potential treatment target for male infertility.