The IbBBX24–IbTOE3–IbPRX17 module enhances abiotic stress tolerance by scavenging reactive oxygen species in sweet potato

Abstract

Soil salinity and drought limit sweet potato yield. Scavenging of reactive oxygen species (ROS) by peroxidases (PRXs) is essential during plant stress responses, but how PRX expression is regulated under abiotic stress is not well understood.Here, we report that the B-box (BBX) family transcription factor IbBBX24 activates the expression of the class III peroxidase gene IbPRX17 by binding to its promoter. Overexpression of IbBBX24 and IbPRX17 significantly improved the tolerance of sweet potato to salt and drought stresses, whereas reducing IbBBX24 expression increased their susceptibility. Under abiotic stress, IbBBX24-and IbPRX17-overexpression lines showed higher peroxidase activity and lower H 2 O 2 accumulation compared with the wild-type. RNA sequencing analysis revealed that IbBBX24 modulates the expression of genes encoding ROS scavenging enzymes, including PRXs.Moreover, interaction between IbBBX24 and the APETALA2 (AP2) protein IbTOE3 enhances the ability of IbBBX24 to activate IbPRX17 transcription. Overexpression of IbTOE3 improved the tolerance of tobacco plants to salt and drought stresses by scavenging ROS.Together, our findings elucidate the mechanism underlying the IbBBX24-IbTOE3-IbPRX17 module in response to abiotic stress in sweet potato and identify candidate genes for developing elite crop varieties with enhanced abiotic stress tolerance.

Regulation of Drought and Salt Tolerance by OsSKL2 and OsASR1 in Rice

“…Accordingly, tolerant species possess a number of ROS detoxifying proteins, such as CAT, POD and SOD, which protect them from oxidative stress (Azevedo-Neto et al 2006). For example, overexpression of IbBBX24 and IbBBX17 in sweet potato improved tolerance to drought and salt stress via scavenging and detoxi cation of ROS (Zhang et al 2022), while transgenic Triticum aestivum overexpressing TaPRX-2A showed increased tolerance to salt as a result of reduced ROS accumulation (Su et al 2020). In this study, overexpression of OsSKL2 in rice reduced H 2 O 2 accumulation and improved the activities of CAT, POD and SOD, thereby enhancing tolerance to drought and salt stress (Fig.…”

A Novel WRKY Transcription Factor from Ipomoea trifida, ItfWRKY70, Confers Drought Tolerance in Sweet Potato

“…Sweet potato ( I. batatas ) is an important food crop; however, its improvement by conventional breeding is limited because its highly heterozygous, generally self-incompatible and outcrossing polyploidy [ 43 ]. Genetic engineering is used to improve the sweet potato [ 5 , 29 , 30 , 31 , 32 ]. The wild ancestor diploid I. trifida acts as an effective resource to improve sweet potato because of its high resistance to abiotic stress [ 37 ].…”

“…The transgenic and the WT plants were transferred to soils in a greenhouse and then in a field for their evaluation. The cuttings about 25 cm in length were used for further function analysis as described by Zhai et al [ 31 ] and Zhang et al [ 32 ].…”

“…Because its highly heterozygous, generally self-incompatible, and outcrossing polyploidy, the conventional breeding in sweet potato faces numerous challenges [ 28 ]. Genetic engineering is an effective way to improve the drought tolerance of sweet potato [ 5 , 29 , 30 , 31 , 32 ]. However, there are few reports about TFs confering tolerance to drought in sweet potato [ 30 , 32 , 33 , 34 , 35 ].…”

“…Genetic engineering is an effective way to improve the drought tolerance of sweet potato [ 5 , 29 , 30 , 31 , 32 ]. However, there are few reports about TFs confering tolerance to drought in sweet potato [ 30 , 32 , 33 , 34 , 35 ]. Diploid Ipomoea trifida (H.B.K.)…”