Wenming Zheng

Wheat leaf rust, caused by Puccinia triticina , poses a continuous threat to global food security. To dissect durable resistance mechanisms, we compared early infection responses between the near‐immune cultivar ‘Yunmai 34’ (YM) and the susceptible ‘Chinese Spring’ (CS). While CS exhibited massive transcriptional reprogramming upon infection, YM displayed a relatively narrow scale‐changes yet could arrested the pathogen prior to haustorium formation. This resistance might be associated with a constitutive immune state, evidenced by elevated basal expression of pathogenesis‐related (PR) genes and defence regulators in the absence of pathogen challenge. Comparatively, CS mobilised a massive differentially expressed genes including those involved in hormone pathways and immune receptors yet insufficient to suppress the pathogen infection. Integrated analysis of differential expression and co‐expression networks identified two defence‐associated genes encoding an LRR‐domain‐containing protein ( TaLRRop ) and an aspartyl‐tRNA synthetase ( TaAspRS ). Functional validation confirmed both as positive regulators contributing to PR‐ and ROS‐associated basal defence. Collectively, these findings demonstrate that a constitutive immune state at the transcriptional level, rather than the overall magnitude of induced responses, underlies effective early resistance to leaf rust, offering valuable target candidates for resistance breeding.

Mycoviruses modulate fungal fitness and pathogenicity, yet their biological roles in obligate biotrophic phytopathogens remain poorly understood. Here, we report the first functional characterization of totiviruses in rust fungi, identifying five novel totiviruses, designated Puccinia triticina totivirus 1 to 5 (PtTV1–PtTV5), from the wheat leaf rust fungus Puccinia triticina ( Pt ). All five PtTVs possess the canonical genomic architecture of Totiviridae , including two overlapping ORFs and a conserved−1 ribosomal frameshifting motif. Transcriptional profiling revealed that PtTVs are highly expressed during early Pt infection. PtTV-encoded proteins suppressed BAX-triggered programmed cell death in Nicotiana benthamiana , indicating immune-suppressive activity. Using BSMV-mediated host-induced gene silencing (HIGS), we showed that knockdown of PtTV transcripts significantly impaired fungal hyphal expansion and uredinial formation, concomitant with enhanced host H₂O₂ accumulation. A survey of 90 Pt field isolates from four major wheat-growing regions of China revealed that PtTVs are ubiquitously distributed in natural rust populations. Collectively, these findings demonstrate that totiviruses function as virulence-promoting symbionts in Pt , establishing for the first time a functional link between totiviral infection and enhanced pathogenicity in cereal rust fungi and identifying candidate targets for RNAi-based disease control. IMPORTANCE: Obligate biotrophic rust fungi represent a major group of plant pathogens with severe global agricultural impacts, yet the biological functions of their native mycoviruses remain largely uncharacterized. This study identifies five novel totiviruses from the wheat leaf rust pathogen Pt and provides the first functional demonstration that totiviruses act as virulence-promoting symbionts in cereal rust fungi. The ubiquitous presence of these viruses across geographically diverse field isolates highlights their broad ecological relevance in natural pathogen populations. These findings advance our understanding of fungus-virus mutualism in obligate biotrophic systems and offer a promising, durable molecular target for RNA-based sustainable management of wheat rust diseases.

Wheat stripe rust ( Puccinia striiformis f. sp. tritici , Pst ) poses a catastrophic threat to global food security. While MADS‐box transcription factors regulate development and abiotic stress, their roles in plant‐pathogen immunity remain enigmatic. In this study, we identified TaMADS2 , a Pst ‐induced MADS‐box gene, as a positive regulator of wheat resistance. Functional analyses demonstrated that TaMADS2 overexpression significantly enhanced Pst resistance, whereas its knockdown rendered wheat more susceptible. Further investigation revealed that TaMADS2 interacts with trichome birefringence‐like protein 21 (TaTBL21) to activate glycerol kinase‐like ( TaGKL ) expression. Silencing TaGKL in wild‐type or TaMADS2 ‐overexpressing lines compromised resistance, with elevated Pst biomass. Notably, dual silencing of TaMADS2 and TaGKL further heightened susceptibility, confirming their synergistic defence role. Mechanistically, the TaMADS2‐TaTBL21 complex promotes wheat resistance to stripe rust disease by upregulating TaGKL expression, leading to the accumulation of the key defence metabolites salicylic acid (SA) and glycerol‐3‐phosphate (G3P). Our study unveils a novel TaMADS2‐TaTBL21‐TaGKL module that potentiates wheat resistance against stripe rust, offering strategic targets for breeding resistant wheat.

Wheat (Triticum aestivum L.) is the most widely cultivated staple food crop globally. As a primary food source for 35–40% of the world’s population, the stability of its yield is directly linked to global food security. However, extreme weather events triggered by climate change have led to reductions in wheat yield, resulting in an urgent need to enhance the stress tolerance of wheat against drought and high temperatures. In this study, we successfully isolated and cloned a myo-inositol oxygenase gene from wheat. Further research revealed that high temperatures and drought stress significantly increased the expression level of the TaMIOXA gene in wheat leaves. A batch of overexpressing lines was obtained via Agrobacterium-mediated transformation. Compared to the control group, wheat plants with molecularly modified TaMIOXA overexpression exhibited stronger resistance to high temperatures and drought. This significantly increased their survival rates by 10% to 40%. The cumulative amount of hydrogen peroxide decreased from 7.86 × 10⁻⁴ to 1.54 × 10⁻² mmol/g, and that of malondialdehyde decreased from 8.42 × 10⁻⁷ to 2.21 × 10⁻⁶ mmol/g. This confirms that overexpression of myo-inositol oxygenase significantly enhances wheat’s tolerance to drought and high temperatures. This study offers valuable genetic resources for wheat stress tolerance.

Wheat (Triticum aestivum L.) is the most widely cultivated staple food crop globally. As a primary food source for 35-40% of the world's population, the stability of its yield is directly linked to global food security. However, extreme weather events triggered by climate change have led to wheat yield reduction, making it an urgent issue to enhance wheat's stress tolerance against drought and high temperatures. In this study, we successfully isolated and cloned an inositol oxidase gene from wheat. Further research revealed that high-temperature and drought stresses significantly increased the expression level of the TaMIOXA gene in wheat leaves. A batch of overexpressing lines was obtained via Agrobacterium-mediated transformation. Compared with the control group, wheat plants with molecularly modified TaMIOXA overexpression exhibited stronger resistance to high temperatures and drought, with their survival rate significantly increased by 10% to 40%. This confirms that overexpression of inositol oxidase significantly enhances wheat's tolerance to drought and high temperatures.

Wheat leaf rust, caused by Puccinia triticina ( Pt ), threatens global wheat production, with yield losses further exacerbated by the pathogen's evolving virulence. Although Syg1/Pho81/Xpr1 (SPX) domain‐containing proteins are known regulators of phosphate homeostasis, their involvement in plant–pathogen interactions remains largely unexplored. We demonstrated that TaSPX3 , a wheat SPX family gene, is rapidly induced during early Pt infection and flg22 treatment. Genetic evidence indicates that TaSPX3 is a positive regulator of rust resistance, with knockdown lines showing increased susceptibility and overexpression lines exhibiting enhanced resistance. Using yeast two‐hybrid screening, we identified TaDi19‐1D, a zinc finger transcription factor, as a direct TaSPX3 interactor. TaDi19‐1D functions as a negative immune regulator by suppressing the expression of pathogenesis‐related (PR) genes ( TaPR1 , TaPR2 , TaPR5 ) through direct promoter binding. TaSPX3 counteracts this repression by physically interacting with TaDi19‐1D, thereby derepressing PR gene expression and boosting wheat resistance to Pt . Our findings revealed a novel TaSPX3–TaDi19 regulatory module that fine‐tunes TaPRs expression, providing mechanistic insights into pattern‐triggered immunity (PTI) and potential genetic targets for breeding durable broad‐spectrum disease‐resistant wheat varieties.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), poses a significant threat to wheat production, particularly in Henan Province, which produces more than 36 million tons of wheat grain every year, the highest production among all provinces in China. This study characterized 219 Pst isolates collected from the five regions of Henan through virulence testing using two sets of wheat differentials and genotyping with 23 Kompetitive allele-specific PCR (KASP) markers developed from single nucleotide polymorphism (SNP) markers. Based on the virulence phenotypes on the Chinese differentials, 37 races were identified, including 17 new races. CYR34, CYR32, and G22-14 were the top three most prevalent races across the province. The virulence profiles varied among the five regions. The tests of the isolates with the Yr single-gene differentials revealed 75 races. None of the isolates were virulent to either Yr5 or Yr15, whereas the virulence frequencies to the other 16 Yr genes varied from 10 to 85% in the province and were slightly different among the five regions for each virulence factor. The Pst populations from the five regions were clustered into two major groups based on the two sets of differentials and the KASP-SNP marker data. These findings provide valuable insights for developing wheat cultivars with effective resistance for enhancing stripe rust management and improving wheat yields in Henan Province and the country.