Arbuscular mycorrhizae status of host plant affects offspring’s phenotype and transcriptome expression in a low-phosphorus environment

Although the effects of arbuscular mycorrhizal fungi(AMF)on host plants have been well documented,whether the effects of AMF on parental generations affect offspring performance is not fully clear.We conducted a common garden experiment to determine whether AMF status of host plants(Medicago truncatula)affects phenotype and transcriptome expression of their offspring.Seeds from four type parental treatments(low-phosphorus(P)soil without AMF,low-P soil with AMF,high-P soil without AMF and high-P soil with AMF)were grown under low-P(LPS)and normal-P soil(OHS)conditions.The fowering pattern of LP offspring was similar to their parents,such that plants with AMF fowered earlier than those without AMF under OHS condition but were opposite under LPS condition.The transcriptome differential analysis showed that some differential transcripts(45 for parental plants growing under low-P condition and 3 for parental plants growing under high-P condition)expression patterns between offspring were comparable,and that only affected by parental AMF status regardless of the P environment that offspring was grown.Others(146 for parental plants growing under low-P condition and 2 for parental plants growing under high-P condition),however,were affected both by the parental AMF status and the offspring P environment.In addition,the number of differential transcripts between offspring whose parental plants grew under high-P condition was far less than under low-P condition.These results indicate that AMF may not only affect the current generation of host plants but also affect the offspring especially when their parents have experienced a stressful environment.

Vitamin D_3 increased intestinal Na/Pi-Ⅱb and CYP27B1 mRNA level in rats fed low-phosphorus diets

The objective of the study was to determine the role of vitamin D3(VD3) in regulating adaptation and mechanism of rats to low-phosphorus(P) diets. Rats were assigned to 4 diets containing 0.2%, 0.4%, 0.6%,or 0.8% P consisting of 5 replicate cages with 6 rats per replicate cage and fed for 7 days. Four rats from each replicate cage were treated with ethane-1-hydroxy-1,1-diphosphonicacid, tetrasodium salt(EHDP)and 2 rats remained untreated. Twelve hours prior to preparation on d 7, two of the EHDP-treated rats received an intraperitoneal injection of VD3 [1,25-(OH)_2 D_3] at 600 ng per kg body weight, while two rats did not receive the injection. Rats that did not receive VD_3 injection had decreased(P < 0.001) P absorption, but injection of VD3 resulted in increased(P < 0.001) absorption. The effect of VD3 injection was greater(P < 0.001) for rats fed 0.2% P diet than rats fed 0.8% P diet in ileum. Sodium dependent phosphate cotransporter type IIb(Na/Pi-IIb) and 25-hydroxyvitamin D 1-α hydroxylase(CYP27 B1) mRNA level showed the same trend with P absorption. Serum concentration of VD3 and la-hydroxylase activity in rats fed 0.2% P diet were lower than those fed 0.8% P diet. The injection of VD3 increased(P < 0.001)serum concentration of VD3 and la-hydroxylase activity. Thus, VD3 increased Na/Pi-Ⅱb and CYP27 B1 mRNA level and improved serum concentration of VD3 and la-hydroxylase activity in rats fed low-P diets.