Aims: Spodoptera exigua is a serious pest of many agricultural crops. However, the bacterial communities of S. exigua are poorly studied, particularly over their entire life cycle. We aimed to study the biodiversity of the microbiota across the life cycle of S. exigua and to provide a better and obtain insight into new pest control strategies. Methods and Results: The bacterial diversity across the life cycle of S. exigua was studied using Illumina MiSeq sequencing of 16S rRNA genes. Spodoptera exigua is dominated by Proteobacteria and Firmicutes, with a total relative abundance of 90Á03%. Enterococcus (24Á6%), Pseudomonas (12Á2%) and Asaia (45Á9%) were abundant and active in eggs, while Methylobacterium (18Á7%) and Halomonas (16Á5%) dominated freshly eclosed larvae. The 3rd and 5th instar larvae were dominated by Enterococcus (76Á3 and 62Á0%). Pupal stages had the highest microbial diversity. There was no significant difference between newly emerged males and females. Symbionts of eggs were extremely similar and probably vertically transmitted by males during mating. Conclusions: The result showed that the bacterial community was affected by the host developmental stages. Our results also suggest that symbionts of egg mass are probably vertically transmitted control by male spawning adults. Significance and Impact of the Study: Our study documents the symbiont bacteria across the life cycle of S. exigua. Understanding the microbial symbionts may provide clues to develop potential biocontrol techniques against this pest.

Increasing the alpha-linolenic acid (LNA; 18:3 cis-9,cis-12,cis-15) content of milk fat might help promote consumers' health. The objective of this study was to determine the potential to alter the content of LNA in milk by duodenal infusion of a free fatty acid mixture rich in LNA. Four multiparous lactating Chinese Holstein cows fitted with duodenal cannulas were administered 2 treatments in a crossover design: an LNA-rich fatty acid infusion at varying concentrations (0, 40, 80, 120, and 160 g/d) versus a basal infusate control. Dry matter intake was not affected by LNA infusions. Milk production tended to decrease and was quadratically affected as LNA infusion increased, but 4% fat-corrected milk yield was not changed. Milk fat content tended to increase linearly with LNA infusion. Milk protein content was not changed by LNA infusion, whereas milk lactose content and yield were decreased quadratically as LNA infusion increased. Increasing the amount of LNA infused into the duodenum linearly increased concentrations of 18:3 cis-9,cis-12,cis-15 (0.61 to 25.4 g/100g of total fatty acids) and 18:2 cis-9,cis-12 in milk fat. Increasing LNA decreased the percentages of 4:0, 14:0, and 16:0 fatty acids linearly. Increasing LNA also linearly decreased the percentages of 18:1 cis-9 and 18:2 cis-9,trans-11 in milk fat. Milk fat content of 20:5 cis-5,cis-8,cis-11,cis-14,cis-17 was quadratically affected, whereas concentrations of 18:0, 18:1 trans-9, 18:1 trans-11, and 18:2 trans-10,cis-12 were not affected. Increasing the supply of 18:3 cis-9,cis-12,cis-15 to the small intestine linearly increased 18:3 cis-9,cis-12,cis-15 in milk fat and markedly altered milk fat composition.

Sheath blight, caused by Rhizoctonia solani AG1-IA, is one of the most serious diseases of rice. In this study, a total of 175 isolates of R. solani AG1-IA were collected from five rice-growing regions in China. Pathogenicity tests revealed that all isolates were virulent to five cultivars with different levels of resistance at the rice seedling stage in the greenhouse. There was considerable variation in aggressiveness, and the isolates were classified into three pathotypes based on disease severity, with moderately virulent isolates prevalent in the population. Forty-three haplotypes were identified based on ITS sequencing, and 39 haplotypes were distinct among isolates. There were high levels of haplotype diversity and nucleotide diversity within the populations of R. solani AG1-IA. High gene flow (Nm = 1Á63-5Á22) was detected, consistent with relatively low differentiation between pairs of populations. Five populations were divided into two distinct clusters by the unweighted pair group method with arithmetic mean (UPGMA), and no spatial population differentiation was discernible. The majority (97Á8%) of genetic diversity was distributed among isolates within populations, with only 2Á2% of the genetic diversity attributed to differences among populations. The star-like shape of the haplotype network provided evidence of signatures of population expansion in recent history. No significant relationships were found between the genetic diversity and aggressiveness or geographic origin among populations of R. solani AG1-IA. These results highlight that the population characteristics of R. solani AG1-IA should be taken into account in evaluating the germplasm resistance of rice cultivars to sheath blight.

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