Characterization and Genetic Analysis of a Light‐ and Temperature‐sensitive Spotted‐leaf Mutant in Rice

Abstract

A rice spotted-leaf mutant was isolated from an ethane methyl sulfonate (EMS) -induced IR64 mutant bank. The mutant, designated as spl30 (spotted-leaf30), displayed normal green leaf color under shade but exhibited red-brown lesions under natural summer field conditions. Initiation of the lesions was induced by light and the symptom was enhanced at 33 (°) C relative to 26 (°) C. Histochemical staining did not show cell death around the red-brown lesions. Chlorophyll contents in the mutant were significantly lower than those of the wild type while the ratio of chlorophyll a/b remained the same, indicating that spl30 was impaired in biosynthesis or degradation of chlorophyll. Disease reaction patterns of the mutant to Xanthomonas oryzae pv. oryzae were largely unchanged to most races tested except for a few strains. Genetic analysis showed that the mutation was controlled by a single recessive gene, tentatively named spl30(t), which co-segregated with RM15380 on chromosome 3, and was delimited to a 94 kb region between RM15380 and RM15383. Spl30(t) is likely a novel rice spotted-leaf gene since no other similar genes have been identified near the chromosomal region. The genetic data and recombination populations provided in this study will enable further fine-mapping and cloning of the gene.

Characterization and Genetic Analysis of a Novel Rice Spotted‐leaf Mutant HM47 with Broad‐spectrum Resistance to Xanthomonas oryzae pv. oryzae

“…Environmental factors play an important role in the initiation of leaf lesions in some spl mutants. The spl30 lesions are induced by light, and the severity of the symptom is enhanced by elevated temperatures (Huang et al ). It is generally believed that UV‐light is responsible for the initiation of lesions (Yamanouchi et al ).…”

“…The genetic controls of more than 55 rice spl mutants have been clarified, and a small numbers of genes have been isolated (Kiyosawa ; Yoshimura et al ; Yin et al ; Wu et al ; Chen et al ; Huang et al , ; Babu et al ; Feng et al ). The majority of the spl traits are controlled by single recessive genes, while a few of them are governed by dominant, double‐recessive or maternal genes (Wang et al ; Wu et al ; Huang et al ).…”

Fine mapping and candidate gene analysis of LM3, a novel lesion mimic gene in rice

“…Rice LMMs have been isolated from natural variants or by chemical and physical mutagenesis, and more than 100 rice LMMs have been found to date (Liu et al 2003). Genetic analysis has indicated that the majority of rice LMMs are controlled by single recessive or dominant genes (Wu et al 2008;Huang et al 2010;2011). Seven rice lesion mimic (or spotted leaf) genes have been cloned: Spl7, Spl11, OsLSD1, OsAT1, OsPti1a, Spl28 and SL (Yamanouchi et al 2002;Zeng et al 2004;Wang et al 2005;Mori et al 2007;Takahashi et al 2007;Qiao et al 2010;Fujiwara et al 2010).…”

“…To our knowledge, two spotted leaf genes have been mapped to rice chromosome 3: spl-3 and Spl30 (t) (Yoshimura et al 1997;Huang et al 2011). The spl-3 gene was mapped between RFLP markers XNpb173 and XNpb348 on rice chromosome 3 (Yoshimura et al 1997); according to the Gramene database, spl-3 and bl4 (or lrd9) are the same gene.…”

“…Further information about spl-3 has not been reported to date. The other spotted leaf gene, Spl30 (t), was localised to a 348 kb chromosome segment flanked by markers HQN225 and RM15383 (Huang et al 2011).…”