Setosphaeria turcica is limited.  In this study, eight StLysM genes are identified and designated as StLysM1 to StLysM8.  The analysis of sequence features indicates that five proteins (StLysM1, StLysM2, StLysM5, StLysM6, and StLysM7) are potential effectors.  Phylogenetic analysis suggests that the StLysMs are divided into fungal/bacterial and fungus-specific subclasses.  Domain architecture analysis reveals that the five StLysM effectors exclusively harbor the LysM domain, whereas the other three StLysM proteins contain additional functional domains.  Sequence conservation analysis shows that the fungal-specific LysM domain sequences share the ⁸GDxTC¹² and ²⁹WNP³¹ motifs as well as three highly conserved cysteine residues.  Conversely, the LysM domain sequences from the bacterial/fungal branch have few conserved sites.  Moreover, expression profiling analysis shows that the StLysM1 gene is significantly upregulated during the infection of maize.  Yeast secretion assays and transient expression experiments demonstrate that StLysM1 is a secreted protein that can suppress BAX/INF1-induced programmed cell death in Nicotiana benthamiana.  Further functional analysis suggests that StLysM1 cannot interact with itself but it can bind chitin.  The transient expression of StLysM1 inhibits the chitin-triggered plant immune response, increasing susceptibility to the phytopathogenic fungus Botrytis cinerea in N. benthamiana.  This study reveals that the S. turcica LySM protein family consists of eight members, highlighting the significance of StLysM1 as a vital effector in regulating plant immunity.  The results provide insight into StLysMs and establish a foundation for understanding the roles of StLysM proteins in the pathogenic process of S. turcica.

In Brassica napus L. (rapeseed), complete genic male sterility (GMS) plays an important role in the utilization of heterosis.  Although microRNAs (miRNAs) play essential regulatory roles during bud development, knowledge of how GMS is regulated by miRNAs in rapeseed is rather limited.  In this study, we obtained a novel recessive GMS system, CN12AB.  The sterile line CN12A has defects in tapetal differentiation and degradation.  Illumina sequencing was employed to examine the expression of miRNAs in the buds of CN12A and the fertile line CN12B.  We identified 85 known miRNAs and 120 novel miRNAs that were expressed during rapeseed anther development.  When comparing the expression levels of miRNAs between CN12A and CN12B, 19 and 18 known miRNAs were found to be differentially expressed in 0.5–1.0 mm buds and in 2.5–3.0 mm buds, respectively.  Among these, the expression levels of 14 miRNAs were higher and the levels of 23 miRNAs were lower in CN12A compared with CN12B.  The predicted target genes of these differentially expressed miRNAs encode protein kinases, F-box domain-containing proteins, MADS-box family proteins, SBP-box gene family members, HD-ZIP proteins, floral homeotic protein APETALA 2 (AP2), and nuclear factor Y, subunit A.  These targets have previously been reported to be involved in pollen development and male sterility, suggesting that miRNAs might act as regulators of GMS in rapeseed anthers.  Furthermore, RT-qPCR data suggest that one of the differentially expressed miRNAs, bna-miR159, plays a role in tapetal differentiation by regulating the expression of transcription factor BnMYB101 and participates in tapetal degradation and influences callose degradation by manipulating the expression of BnA6.  These findings contribute to our understanding of the roles of miRNAs during anther development and the occurrence of GMS in rapeseed.