Identification and Genetic Analysis of a Novel Rice Spotted-Leaf Mutant with Broad-Spectrum Resistance to Xanthomonas oryzae pv. oryzae

Abstract

A spotted-leaf mutant of rice HM143 was isolated from an EMS-induced IR64 mutant bank. Brown lesions randomly distributed on leaf blades were observed about 3 wk after sowing. The symptom lasted for the whole plant growth duration. Histochemical analysis indicated that cell death occurred in and around the site of necrotic lesions accompanied with accumulation of hydrogen hyperoxide. Agronomic traits were largely similar to the wild type IR64 except seed setting rate and 1000-grain weight which were significantly decreased in the mutant. Disease resistance of the mutant to multiple races of Xanthomonas oryzae pv. oryzae was significantly enhanced. Genetic analysis showed that the mutation was controlled by a single recessive gene, tentatively termed spl HM143. In addition, using molecular markers and 1023 mutant type individuals from an F2 segregating population derived from the cross HM143/R9308, the spotted-leaf gene was finally delimited to an interval of 149 kb between markers XX25 and ID40 on the long arm of chromosome 4. Spl HM143 is likely a novel rice spotted-leaf gene since no other similar genes have been identified near the chromosomal region.

Identification of a Novel Semi-Dominant Spotted-Leaf Mutant with Enhanced Resistance to Xanthomonas oryzae pv. oryzae in Rice

“…It has been shown that cell death is detected in/around the lesions of spl11 , HM47 and spl33 in rice using trypan blue staining [2,7,13]. In addition, the cell death is likely caused by the burst of ROS in the mutants mentioned above as well as the rice HM143 and sorghum ded1 [4,41]. In the present study, spl24 shows HR-like PCD with dosage effect.…”

“…Among these mutants, spl30 generates red-brown lesions without detectable cell death probably due to the accumulation of unknown pigments [3]. Except spl30 , the other spotted-leaf mutants exhibit necrotic lesions with accumulation of reactive oxygen species (ROS) and cell death at/around the lesions [2,4,5]. So far, approximately 20 spotted-leaf genes have been isolated and characterized.…”

A semi-dominant mutation in a CC-NB-LRR-type protein leads to a short-root phenotype in rice

“…Many lesion-mimic mutants have been isolated in rice, and almost all of these lesions were observed on the leaf blades or sheaths (Shen et al 2014 ; Takahashi et al 1999 ; Tang et al 2011 ; Wu et al 2008 ; Yin et al 2000 ). In this study, we describe a semi-dominant mutant, nrtp1-D .…”

A Novel Allele Encoding 7-Hydroxymethyl Chlorophyll a Reductase Confers Bacterial Blight Resistance in Rice

“…x FOR PEER REVIEW 8 of 15 It has been reported that HM143 enhances disease resistance to multiple bacterial blight pathogens [9]. To access the disease response to bacterial blight pathogens in the OE lines, we performed bacterial inoculation of five different bacterial blight races, namely C3, C6, JS97-2, PXO347, and PXO349, between the Kitaake and OE-4 lines.…”

“…The three indicative lines were used for comprehensive characterization. To verify the off-target effect, we obtained 20 off-target sites from the CRISPR-P website (http://cbi.hzau.edu.cn/cgi-bin/CRISPR, accessed on 23 June 2021) (Supplementary Table It has been reported that HM143 enhances disease resistance to multiple bacterial blight pathogens [9]. To access the disease response to bacterial blight pathogens in the OE lines, we performed bacterial inoculation of five different bacterial blight races, namely C3, C6, JS97-2, PXO347, and PXO349, between the Kitaake and OE-4 lines.…”