KINGDOM CLASSIFICATION was proposed by R.H. Whittaker. Five kingdoms defined in this classification were named Monera, PROTISTA, Fungi, Plantae, and Animalia.All the bacteria comes under kingdom monera.Explanation-Citrus canker is a disease of plants caused by the bacterium Xanthomonas citri.Xanthomonas is a gram-negative bacteria.Most of the PATHOGENIC bacteria are from the gram-negative group.Xanthomonas causes DAMAGE to the plant leaves, stem, and fruit.The infection causes by citrus trees, including lime, oranges, and grapefruit. BacteriaDiseaseMycobacterium tuberculosisTuberculosisMycobacterium lepraeLeprosyCorynebacterium diphtheriaeDiptheriaClostridium tetaniTetanusSalmonella typhiTyphoidBacillus anthracisAnthraxXanthomonas citriCitrus canker