Genetic and molecular mechanisms underlying the male sterility in rice

Male reproductive development is a complex and highly ordered phenomenon which demands comprehensive understandings of underlying molecular mechanisms to expand its scope for crop improvement. Genetic manipulation of male fertility/sterility is critical for crop hybrid breeding. Although male sterility is not a good trait for the plant itself, its wider application in hybrid rice breeding has made it valuable. The currently widely used male sterile line breeding systems mainly include the following: three-line hybrid rice based on cytoplasmic male sterility and two-line hybrid rice based on environmentally sensitive gene male sterility. The study of male sterility is an excellent thoroughfare to critically understand the regulatory mechanisms essential for the complicated male reproductive developmental process. The unique trait of male sterility also provides valuable resources and convenience for the genetic improvement of rice hybrids. Therefore, deeper and broader understandings about the genetic causes of male sterility are necessary for both basic studies and rice genetic improvement.