Characterization and mapping of a spotted leaf mutant in rice (Oryza sativa)

Abstract

Spotted leaf mutant belongs to a class of mutants that can produce necrotic lesions spontaneously in plants without any attack by pathogens. These mutants have no beneficial effect on plant productivity but provide a unique opportunity to study programmed cell death in plant defense responses. A novel rice spotted leaf mutant (spl30) was isolated through low-energy heavy ion irradiation. Lesion expression was sensitive to light and humidity. The spl30 mutant caused a decrease in chlorophyll and soluble protein content, with marked accumulation of reactive oxygen species (ROS) around the lesions. In addition, the spl30 mutant significantly enhanced resistance to rice bacterial blight (X. oryzae pv. oryzae) from China (C1–C7). The use of SSR markers showed that the spl30 gene was located between markers XSN2 and XSN4. The genetic distance between the spl30 gene and XSN2 and between spl30 and XSN4 was 1.7 cM and 0.2 cM, respectively. The spl30 gene is a new gene involved in lesion production and may be related to programmed cell death in rice. The ability of this mutant to confer broad resistance to bacterial blight provides a model for studying the interaction between plants and pathogenic bacteria.

Characterization and Genetic Analysis of a Novel Light-Dependent Lesion Mimic Mutant, lm3, Showing Adult-Plant Resistance to Powdery Mildew in Common Wheat

“…PCD was also demonstrated by a DNA laddering during lesion formation (data not shown). To confirm that ROS accompanied PCD, we performed a DAB staining assay to assess H 2 O 2 accumulation, in which a reddish-brown polymer precipitate is generated by the interaction between DAB and H 2 O 2 in the presence of peroxidase [ 61 ]. After staining, a large amount of reddish-brown precipitate was only observed at necrotic sites in the lm3 mutant leaves ( Fig 4E–4H ), and dark reddish-brown staining appeared with increasing severity of necrosis ( Fig 4F and 4H ), indicating a high level of H 2 O 2 accumulation in the lm3 mutant.…”

“…The spl30(t) lesions were induced through light, including fluorescent light, and enhanced by higher temperatures [ 22 ], whereas the lesions of the rice Oslsd1 mutant were induced at a lower temperature and under shorter duration of daylight [ 1 ]. Moreover, the expression of lesion spots in spl30 mutants is sensitive to light and humidity [ 61 ]. In the present study, no visible lesions were detected under the 0 -h photoperiod, but lesions appeared under illumination, indicating that the mutant was light dependent, similar to the LF2010A mutant [ 14 ] and the LM lines derived from the Yanzhan1/Zaosui30 cross [ 13 ].…”

SPL33, encoding an eEF1A-like protein, negatively regulates cell death and defense responses in rice

“…These mutants spontaneously develop localized cell death lesions resembling those caused by HR in the absence of pathogen infection, abiotic stress or mechanical damage (Xu et al , 2014). Many LMMs display significantly enhanced resistance to disease (Wang et al , 2015 a ; Wang et al , 2015 b ) and it is believed that such mutants are ideal tools for deciphering the signal pathways of PCD and defense responses in plants.…”

Functional inactivation of OsGCNT induces enhanced disease resistance to Xanthomonas oryzae pv. oryzae in rice

“…The hypersensitive response (HR), a type of PCD, is the most common characteristic of plant disease resistance, which triggers rapid cell death to inhibit further invasion of pathogens in host plant tissues [ 3 ]. Lesion mimic mutants (LMMs) or the specifically termed spotted-leaf (spl) mutants in rice could produce necrotic lesions similar to that caused by HR without pathogen infection, abiotic stress or mechanical damage [ 4 ]. In fact, it has been reported that numerous rice spl mutants display significantly enhanced disease resistance to multiple pathogens [ 5 , 6 ].…”