Effect of dry mycelium of Penicillium chrysogenum on the growth and physiological performance of Trifolium repens and Lolium perenne

Aims The application of growth promoter is an important tool for ecological restoration of degraded grassland by human intervention. Therefore, the aim of this study is to investigate the growth promoting effect of dry mycelium of Penicillium chrysogenum (DMP), a residue from the industrial production of penicillin, on the growth and physiological performance of Trifolium repensand Lolium perenne. Methods In this study, we mainly applied pot experiment and field experiment to investigate the growth promoting effect of DMP addition on the performance of T. repens and L. perenne. Then we applied transcriptome sequencing to determine the molecular mechanism of DMP promoting effects on forage growth. Important findings The results of this study are as follows: (1) DMP addition can significantly improve their physiological indices and enhanced developmental morphological traits of T. repens and L. perenne. Compared with the compound fertilizer treatment, the application of 4.50 g DMP per pot significantly increased the plant height, tiller number and leaf number of L. perenne, and the application of 2.25 g DMP per pot significantly increased the plant height, branching number and leaf number of T. repens, while 4.50 g·pot-1 of DMP significantly increased the total chlorophyll content, crude protein content and crude fat content of L. perenne, and this concentration of DMP addition also significantly increased the total chlorophyll and crude protein contents of T. repens. (2) DMP addition can increase the biomass of L. perenne and T. repens. Under potting conditions, DMP application significantly increased aboveground fresh and dry mass of L. perenneand T. repens compared with compound fertilizer treatment. DMP at 225 kg·hm-2 also increased aboveground and belowground dry mass accumulation of L. perenneand T. repensunder low temperature and low sunlight field conditions in Zhaotong. (3) Transcriptome sequencing showed that DMP treatment induced the expression of genes related to phytohormone biosynthesis and signal transduction pathways in L. perenne, confirming that DMP promotes forage growth by inducing hormone biosynthesis and signal transduction pathways. This study first demonstrates that DMP can promote the growth of forage, and proposes a new strategy of using DMP as a growth promoter, which provides new ideas for the restoration and sustainable development of degraded grasslands under low temperature and low sunlight conditions.