Abstract: Although the effects of arbuscular mycorrhizal fungi (AMF) on host plants have been well documented, whether the effects of AMF on parental generations could affect offspring performance is not fully clear. We conducted a common garden experiment to determine whether AMF status of host plants (Medicago truncatula) affect 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 flowering pattern of LP offspring was similar to their parents that plants with AMF flowered earlier than those without AMF under OHS condition but was 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 similar, and only affected by parental AMF status regardless of the P environment that offspring grew. 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. Meanwhile, the number of differential transcripts between offspring whose parental plants grew under high-P condition were 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.

Key words: Arbuscular mycorrhizal fungi, low phosphorus environment, flowering pattern, transgenerational effects, transcriptome differential analysis