In our previous research, we found that trichokonins’ (TKs) employment improved the thermotolerance of the Lanzhou lily, a renowned edible crop species endemic to China that is relatively susceptible to high temperatures (HTs). Here, a novel Lanzhou lily GRAS gene, LzSCL9, was identified to respond to heat stress (HS) and HS+TKs treatment based on transcriptome and RT-qPCR analysis. TKs could improve the upregulation of LzSCL9 during long-term HS. The expression profile of LzSCL9 in response to HS with or without TKs treatment showed a significant positive correlation with LzHsfA2a-1, which was previously identified as a key regulator in TKs’ conferred resilience to HT. More importantly, overexpression of LzSCL9 in the lily enhanced its tolerance to HTs and silencing LzSCL9 in the lily reduced heat resistance. Taken together, this study identified the positive role of LzSCL9 in TK-induced thermotolerance, thereby preliminarily establishing a molecular mechanism on TKs regulating the thermostability of the Lanzhou lily and providing a new candidate regulator for plant heat-resistant breeding.

Lanzhou lily is a plant native to China with high edible, medicinal, and ornamental value that is relatively susceptible to Fusarium wilt. In this study, the application of Trichoderma longibrachiatum SMF2 (TlSMF2) effectively controlled Lanzhou lily wilt disease caused by Fusarium oxysporum and F. solani. TlSMF2 and the antimicrobial peptaibols trichokonins (TKs) produced by TlSMF2 inhibited the mycelial growth and spore germination of these two pathogens. Transcriptome analysis revealed that the TKs-induced defense responses of Lanzhou lily were mainly related to the production of plant hormones and defense enzymes. In detail, TKs treatment increased the levels of salicylic acid (SA) and jasmonic acid (JA) and the expression of their related genes and upregulated the activities of chitinase and phenylalanine ammonia-lyase (PAL). Moreover, TKs caused the induction of LzWRKY26 and LzWRKY75, which is highly homologous to LrWRKY3 that positively regulates Lilium regale resistance to F. oxysporum. LzWRKY26 expression was also induced by SA and MeJA treatments and F. oxysporum infection, which was consistent with the findings that many cis-acting elements associated with phytohormones and stress responses are present in the promoter region of LzWRKY26. Therefore, the biocontrol mechanisms of TlSMF2 against Lanzhou lily wilt disease involve substrate competition and toxicity against pathogens, as well as the induction of systemic resistance in plants. Our results highlight a promising biological control agent for soil-borne fungal diseases and offer deeper insights into the biocontrol mechanisms of TlSMF2.

Lilies are one of the most popular ornamental flowers in the world. However, the abundant pollen produced in their anthers causes significant inconvenience for producers and consumers. Pollen abortion induced by molecular breeding techniques is one of the effective ways to solve this problem. In this study, the LoTDF1 gene, which is involved in regulating lily anther development, was identified and cloned from lily anthers based on transcriptome data. The open reading frame of LoTDF1 is 936 bp and encodes a protein with 311 amino acids. Multiple sequence alignment and phylogenetic tree analysis revealed that the LoTDF1 protein contained a conserved R2R3 domain, belonging to the MYB transcription factor family. Subcellular localization and transcriptional activation assays demonstrated that LoTDF1 localized to the nucleus and functioned as a transcription activator. The transcriptional activation domain was located within the last 195 amino acids (117–311a) of the C-terminus, and there may be more than one transcriptional activation domain in the region. The expression level of the LoTDF1 gene was highest during the pollen mother cell (PMC) stage of lily anther development (2 cm anther), followed by the tetrad stage (4 cm anther). In situ hybridization experiments further confirmed that LoTDF1 transcripts were predominantly localized in PMCs, tapetal cells, middle layer cells, dyads, and tetrads. The experiment data suggest that LoTDF1 plays a critical role in regulating early anther development in lily. LoTDF1 could be a promising candidate gene for molecular breeding strategies aimed at developing pollen-free lily cultivars to enhance commercial and consumer appeal.