Penicillium verrucosum contaminates temperate cereals with ochratoxin A (OTA) during harvesting and storage. We examined the effect of temperature (25 vs 30 oC), CO2 (400 vs 1000 ppm) and matric/solute stress (-2.8 vs -7.0 MPa) on (i) growth, (ii) key OTA biosynthetic genes and (iii) OTA production on a milled wheat substrate. Growth was generally faster under matric than solute stress at 25 oC, regardless of CO2 concentrations. At 30 oC, growth of P. verrucosum was significantly reduced under solute stress in both CO2 treatments, with no growth observed at -2.8 MPa (=0.98 water activity, aw) and 1000 ppm CO2. Overall, growth patterns under solute stress was slower in elevated CO2 than under matric stress when compared with existing conditions. The otapksPV gene expression was increased under elevated CO2 levels in matric stress treatments. There was fewer effects on the otanrpsPV biosynthetic gene. This pattern was paralleled with the production of OTA under these conditions. This suggest that P. verrucosum is able to actively grow and survive in both soil and on crop debris under three way interacting climate-related abiotic factors. This resilience suggests that they would still be able to pose an OTA contamination risk in temperate cereals post-harvest.

中文翻译：

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溶质/基质胁迫与气候变化非生物因素对小麦基质上疣状青霉生长、基因表达和赭曲霉毒素 aA 产生的动力学影响

疣状青霉在收获和储存过程中会用赭曲霉毒素 A (OTA) 污染温带谷物。我们检查了温度（25 与 30 oC）、CO2（400 与 1000 ppm）和基质/溶质应力（-2.8 与 -7.0 MPa）对 (i) 生长、(ii) 关键 OTA 生物合成基因和 (iii) 的影响在磨碎的小麦基质上生产 OTA。无论 CO2 浓度如何，基质在 25 oC 下的生长速度通常都快于溶质胁迫。在 30 oC 时，两种 CO2 处理在溶质胁迫下都显着降低了疣状假单胞菌的生长，在 -2.8 MPa（=0.98 水活度，aw）和 1000 ppm CO2 下没有观察到生长。总体而言，与现有条件相比，在 CO2 升高的溶质胁迫下的生长模式比在基质胁迫下的生长模式要慢。在基质胁迫处理中，在 CO2 水平升高的情况下，otapksPV 基因表达增加。对 otanrpsPV 生物合成基因的影响较小。在这些条件下，这种模式与 OTA 的生产是平行的。这表明 P. verrucosum 能够在三种相互作用的气候相关非生物因素下在土壤和作物残骸中积极生长和生存。这种弹性表明它们仍然能够在收获后的温带谷物中造成 OTA 污染风险。